Comtech EF Data SMS-758 User Manual

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SMS-758

SMS-758SMS-758

Modem Protection Switch

Modem Protection SwitchModem Protection Switch Installation and Operation Manual

Installation and Operation Manual

Installation and Operation ManualInstallation and Operation Manual

Part Number MN/SMS758.IOM Revision 3

EFData Corporation is an ISO 9001 Registered Company

SMS-758

SMS-758SMS-758

Modem Protection Switch

Modem Protection SwitchModem Protection Switch Installation and Operation Manual

Installation and Operation Manual

Installation and Operation ManualInstallation and Operation Manual

Part Number MN/SMS758 Revision 3 May 19, 1995

EFData Top Assembly No. AS/1891

Special Instructions:

This is the fourth edition of the manual. Change bars were not utilized. This revision supersedes part number MN/U-SMS758 Edition 3 dated January, 1992.

Comtech EFData, 2114 West 7th Street, Tempe, Arizona 85281 USA, (480) 333-2200, FAX: (480) 333-2161.

Warranty Policy

This EFData Corporation product is warranted against defects in material and workmanship for a period of one year from the date of shipment . Duri ng the warranty period, EFData will, at its option, repair or replace produc t s that prove to be defective.

For equipment under warranty, the customer is responsible for freight to EFData and all related custom, taxes, tariffs, insurance, etc. EFDat a i s responsible for the freight charges return the equipment by the same method (i.e., A i r, Express, Surface) as the equipment was sent to EFDat a.

for return of the equipment f rom the factory to the customer. EFDat a will

only

Limitations of Warranty

The foregoing warranty shall not apply to defects resulting from i mproper installation or maintenance, abuse, unaut horized modification, or operation outside of environmental specifi cations for the product, or, for damages that occur due to improper repackaging of equipment for return to EFData.

No other warranty is expressed or implied. EFData Corporation specifically disclaims the implied warranties of merchantability and fitness for particular purpose.

Exclusive Remedies

The remedies provided herein are the buyer's sole and exclusive remedies. E FData Corporation shall not be liable for any direct, indirect, special, incidental, or consequential damages, whether bas ed on contact, tort, or any other legal theory.

Disclaimer

EFData has reviewed this manual thoroughly in order that it will be an easy-to-use guide to your equipment. All statements, technical informat i on, and recommendations in this manual and in any guides or rel ated documents are believed reli abl e, but the accuracy and completeness thereof are not guaranteed or warranted, and they are not intended to be, nor should they be unders t ood to be, representations or warranties concerning the products described. Further, EFData reserves the right to make changes in the specifications of the products described in this manual at any time without notice and without obligation to not i fy any person of such changes.

If you have any questions regarding your equipment or the information i n this manual, please contact the EFData Customer Service Depart ment. (For more information, refer to the preface.)

About this Manual

This manual describes the installation and operation for the EFData SMS-758 modem protection switch.

Audience

This is a technical document intended for earth station engineers, technicians, and operators responsible for the operation and maintenance of the SMS-758 modem protection switch.

Organization

This manual includes the following chapters and appendixes:

Preface

Chapter 1 — describes the unit’s purpose, function, and specifications.

•

Chapter 2 — describes the installation process.

•

• Chapter 3 — describes the operation.

Chapter 4 — describes the theory of operation.

•

• Chapter 5 — describes maintenance and troubleshooting.

• Appendix A — describes remote control operation for modem switching.

• Appendix B — describes remote control operation for independent mod/demod

switching.

Appendix C — describes the 7 downlink/1 backup option.

•

MN/SMS758 Rev. 3 i

Preface SMS-758 Modem Protection Switch

Revision Numbering Scheme

The following table identifies the revision numbering scheme utilized for EFData installation and operation manuals, addenda, and supplements:

Part Number Description

MN/SMS758 Rev. 0 1st edition of the manual. MN/SMS758 Rev. 1 1st revision of the manual. MN/SMS758 Rev. 2 2nd revision of the manual. MN/SMS758 Rev. 1

MN/SMS758 Rev. 2 MN/SMS758 Rev. 2 MN/SMS758 Rev. 3 3rd revision of the manual (it includes information from

A B

Supplement A to Rev. 1 of the manual. (The “S” in “SA” designates “Supplement.”) Addendum A to Rev. 2 of the manual. Addendum B to Rev. 2 of the manual.

Addenda A and B).

Conventions Used in this Manual

Screen Output and Command Syntax

A distinctive type of font is used for screen output and command syntax, which looks like this:

This line is in monospace font.

Notes

Note: This is the style for a note.

Cautions, Warnings, and Dangers

The international hazard alert signal is shown below. The signal word listed beneath the symbol is changed to indicate the nature of the hazard. The terms, in increasing order of seriousness, are CAUTION, WARNING, and DANGER.

CAUTION indicates a hazardous situation that, if not avoided, may result in

CAUTION

WARNING

minor or moderate injury. CAUTION may also be used to indicate other unsafe practices or risks of property damage.

WARNING indicates a potentially hazardous situation that, if not avoided,

could result in death or serious injury.

DANGER indicates an imminent hazard that, if not avoided, will result in

DANGER

ii MN/SMS758 Rev. 3

death or serious injury.

SMS-758 Modem Protection Switch Preface

Heading Hierarchy

Each section of this manual is structured according to the following heading hierarchy:

Level Heading Format

1 (Highest) 2

3 4 (Lowest)

Level Heading 1 Level Heading 2

Case Sensitivity

Unless stated otherwise, commands and arguments listed in this manual are not case sensitive.

References Used in this Manual

Military Standards

References to “MIL-STD-118” apply to the 114A series (i.e., MIL-STD-118-114A), which provides electrical and functional characteristics of the unbalanced and balanced voltage digital interface circuits applicable to both long haul and tactical communications. Specifically, these references apply to the MIL-STD-188-114A electrical characteristics for a balanced voltage digital interface circuit, Type 1 generator, for the full range of data rates.

Level Heading 3 Level Heading 4

For more information, refer to the following document:

• Department of Defense (DOD) MIL-STD-188-114A, “Electrical Characteristics

of Digital Interface Circuits.”

Trademarks

Product names mentioned in this manual may be trademarks or registered trademarks of their respective companies and are hereby acknowledged.

MN/SMS758 Rev. 3 iii

Preface SMS-758 Modem Protection Switch

Reporting Comments or Suggestions Concerning this Manual

Comments and suggestions regarding the content and design of this manual will be appreciated. To submit comments, please complete the Technical Publications Remarks Form found at the end of this manual.

Returning a Product

To return an EFData (in-warranty and out-of-warranty) product for repair or replacement:

1. Request a Return Material Authorization (RMA) number from the EFData Customer Service Department.

Be prepared to supply the Customer Service representative with the model number, serial number, and a description of the problem.

2. To ensure that the product is not damaged during shipping, pack the product in its original shipping carton/packaging.

3. Ship the product back to EFData. (Shipping charges should be prepaid.)

For more information regarding the warranty policies, refer to the disclaimer page located behind the title page.

Upgrading a Product

To receive product upgrade information (i.e., hardware and/or software), contact an EFData Customer Service representative.

Product Training

To obtain product training information, contact an EFData Customer Service Representative.

iv MN/SMS758 Rev. 3

CHAPTER 1. INTRODUCTION..................................................................................1–1

1.1 Scope............................................................................................................................................................. 1–1

1.2 Purpose and Function.................................................................................................................................. 1–1

1.3 Description ................................................................................................................................................... 1–2

1.4 Performance Specification........................................................................................................................ 1–10

CHAPTER 2. INSTALLATION...................................................................................2–1

2.1 Unpacking..................................................................................................................................................... 2–1

2.2 System Installation.......................................................................................................................................2–2

2.2.1 Switch Setup........................................................................................................................................... 2–2

2.2.2 Modem Setup......................................................................................................................................... 2–3

2.3 System Requirements.................................................................................................................................. 2–3

2.4 External Connections.................................................................................................................................. 2–4

2.4.1 Data I/O.................................................................................................................................................. 2–5

2.4.2 External RS485 and RS232 Interface (J1 and J2) .................................................................................. 2–6

2.4.3 Modem Control RS485.......................................................................................................................... 2–6

2.4.4 On-Line Status (J4, J5)........................................................................................................................... 2–7

2.4.5 Relay-Remote/Fault (J6)......................................................................................................................... 2–8

2.4.6 Downlink Inputs (J7 through J10, J12 through J15)............................................................................... 2–8

2.4.7 Back-up Demods (J11, J16)................................................................................................................... 2–9

2.4.8 Prime Mod Inputs (J18 through J25)...................................................................................................... 2–9

2.4.9 Back-up Mod Inputs (J26, J36).............................................................................................................. 2–9

2.4.10 Offline IF Outputs (J17, J27) ............................................................................................................... 2–9

2.4.11 IF Outputs (J28 through J35).............................................................................................................. 2–10

2.4.12 AC Power (J37, J38).......................................................................................................................... 2–10

2.4.13 DC Power (J37, J38).......................................................................................................................... 2–10

2.4.14 Ground (J37) ...................................................................................................................................... 2–10

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CHAPTER 3. OPERATION........................................................................................3–1

3.1 Front Panel Description.............................................................................................................................. 3–1

3.1.1 LED Indicators....................................................................................................................................... 3–2

3.1.2 Keypad and LCD Display....................................................................................................................... 3–2

3.2 Switch Setup................................................................................................................................................. 3–6

3.2.1 System Setup.......................................................................................................................................... 3–6

3.2.1.1 Time and Date Menu.......................................................................................................................3–6

3.2.1.2 Downlink Option.............................................................................................................................3–7

3.2.1.3 Active Prime Modulators Menu...................................................................................................... 3–7

3.2.1.4 Active Prime Demodulators Menu.................................................................................................. 3–7

3.2.1.5 Active Backup Modulators Menu................................................................................................... 3–7

3.2.1.6 Active Backup Demodulators Menu............................................................................................... 3–7

3.2.1.7 Modem Addresses Menu................................................................................................................. 3–8

3.2.2 Modem Setup......................................................................................................................................... 3–8

3.2.2.1 Interface Type Menu....................................................................................................................... 3–9

3.2.2.2 Downlink Selection Menu............................................................................................................. 3–10

3.2.2.3 Modulator Priority Menu.............................................................................................................. 3–10

3.2.2.4 Demodulator Priority Menu.......................................................................................................... 3–10

3.2.2.5 Demodulator Delay ....................................................................................................................... 3–11

3.2.2.6 Modulator Delay........................................................................................................................... 3–11

3.2.3 Modem Configuration.......................................................................................................................... 3–12

3.2.3.1 Prime and Backup Modem Configuration..................................................................................... 3–12

3.2.3.2 Modem Configuration Menu......................................................................................................... 3–12

3.2.3.3 Modem Verification...................................................................................................................... 3–13

3.2.4 Faults.................................................................................................................................................... 3–13

3.2.4.1 Modulator Operation Fault............................................................................................................ 3–13

3.2.4.2 Demodulator Operation Fault....................................................................................................... 3–14

3.2.4.3 M:N Faults.................................................................................................................................... 3–14

3.2.4.4 Battery Faults................................................................................................................................ 3–14

3.2.5 Operational Modes............................................................................................................................... 3–15

3.2.5.1 Bypass Mode................................................................................................................................. 3–15

3.2.5.2 Auto Mode.................................................................................................................................... 3–15

3.2.5.3 Local Mode................................................................................................................................... 3–20

3.2.5.4 Remote Mode................................................................................................................................ 3–20

3.2.6 Status Menu.......................................................................................................................................... 3–21

CHAPTER 4. THEORY OF OPERATION..................................................................4–1

4.1 Monitor and Control................................................................................................................................... 4–1

4.1.1 Theory of Operation............................................................................................................................... 4–2

4.1.2 M&C Serial Interface............................................................................................................................. 4–2

4.1.3 Remote Baud Rate.................................................................................................................................. 4–3

4.1.4 Remote Address..................................................................................................................................... 4–3

4.1.5 External Remote Serial Interface Selection............................................................................................ 4–4

4.1.6 Battery.................................................................................................................................................... 4–4

4.1.7 Error Response Function........................................................................................................................ 4–4

4.1.8 External I/O Interrupt Arbitration...........................................................................................................4–5

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4.2 Modem Control Interface Specification..................................................................................................... 4–5

4.3 Relay-Remote Interface Specification........................................................................................................ 4–6

4.3.1 Command Structure................................................................................................................................ 4–6

4.4 Fault Interface Specification....................................................................................................................... 4–9

4.4.1 Controller fault....................................................................................................................................... 4–9

4.4.2 M:N Fault............................................................................................................................................... 4–9

4.4.3 Demodulator Signal Fault..................................................................................................................... 4–10

4.5 Online Status Specification....................................................................................................................... 4–10

4.5.1 Modulator Online Status....................................................................................................................... 4–10

4.5.2 Demodulator Online Status.................................................................................................................. 4–10

4.6 Interface Switches...................................................................................................................................... 4–11

4.6.1 RS-422/449 and MIL-STD-188-114/RS-449 Interface Switch............................................................ 4–11

4.6.1.1 Specification ................................................................................................................................. 4–11

4.6.1.2 Connector Pinouts......................................................................................................................... 4–12

4.6.2 V.35 Interface Switch........................................................................................................................... 4–15

4.6.2.1 Specification ................................................................................................................................. 4–15

4.6.2.2 Connector Pinouts......................................................................................................................... 4–16

4.6.3 V.35/RS-232 Interface Switch.............................................................................................................. 4–19

4.6.3.1 Electrical Specifications................................................................................................................ 4–20

4.6.3.2 Connector Pinouts......................................................................................................................... 4–21

4.6.3.2.1 V.35 Option........................................................................................................................... 4–21

4.6.3.2.2 RS-232 Option....................................................................................................................... 4–22

4.6.4 DS-1 and G.703 Interface Switch......................................................................................................... 4–25

4.6.4.1 Specification ................................................................................................................................. 4–26

4.6.4.2 Connector Pinouts......................................................................................................................... 4–26

4.6.5 IDR Interface Switch............................................................................................................................ 4–29

4.6.5.1 Specification ................................................................................................................................. 4–30

4.6.5.2 Connector Pinouts......................................................................................................................... 4–30

4.6.6 2:N IDR Interface Switch (1877 and 1879).......................................................................................... 4–33

4.6.6.1 Specification ................................................................................................................................. 4–33

4.6.6.2 Operation ...................................................................................................................................... 4–34

4.6.6.3 Connector Pinouts......................................................................................................................... 4–34

4.6.7 2:N IBS/ASYNC Interface Switch (1694 and 1695)............................................................................ 4–38

4.6.7.1 Specification ................................................................................................................................. 4–38

4.6.7.2 Operation ...................................................................................................................................... 4–39

4.6.7.3 Connector Pinouts......................................................................................................................... 4–39

4.7 Address Decoder/Driver............................................................................................................................ 4–44

4.7.1 Specifications....................................................................................................................................... 4–44

4.7.2 Theory of Operation............................................................................................................................. 4–44

4.8 IF Switch Driver ........................................................................................................................................ 4–46

4.8.1 Specifications....................................................................................................................................... 4–46

4.8.2 Theory of Operation............................................................................................................................. 4–46

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4.9 IF Switch..................................................................................................................................................... 4–47

4.9.1 Specifications....................................................................................................................................... 4–47

4.9.2 Theory of Operation............................................................................................................................. 4–47

4.10 Online Telemetry..................................................................................................................................... 4–49

4.10.1 Specifications..................................................................................................................................... 4–49

4.10.2 Theory of Operation........................................................................................................................... 4–49

4.11 Power Supply ........................................................................................................................................... 4–51

4.11.1 Specifications..................................................................................................................................... 4–51

CHAPTER 5. MAINTENANCE...................................................................................5–1

5.1 Fault Descriptions........................................................................................................................................ 5–1

5.1.1 Modulator Operation Fault..................................................................................................................... 5–1

5.1.2 Demodulator Operation Fault................................................................................................................. 5–1

5.1.3 M:N Faults.............................................................................................................................................. 5–2

5.1.4 Battery Faults......................................................................................................................................... 5–2

5.2 Fault Isolation.............................................................................................................................................. 5–3

5.2.1 Modulator Operation.............................................................................................................................. 5–3

5.2.2 Demodulator Operation.......................................................................................................................... 5–4

5.2.3 M:N Operation ....................................................................................................................................... 5–5

5.2.4 Battery.................................................................................................................................................... 5–6

5.3 Module Replacement................................................................................................................................... 5–7

5.3.1 Power Supply......................................................................................................................................... 5–7

5.3.2 IF Switch................................................................................................................................................ 5–8

5.3.3 Switch Driver ......................................................................................................................................... 5–8

5.3.4 Address Decoder/Driver......................................................................................................................... 5–8

5.3.5 M&C ...................................................................................................................................................... 5–8

5.3.6 Online Telemetry.................................................................................................................................... 5–9

5.3.7 Interface Switches.................................................................................................................................. 5–9

5.4 Repacking for Shipment.............................................................................................................................. 5–9

5.4.1 Return Instructions................................................................................................................................. 5–9

5.4.2 Repacking Instructions........................................................................................................................... 5–9

APPENDIX A. REMOTE CONTROL OPERATION: MODEM SWITCH.................... A–1

A.1 General ........................................................................................................................................................A–1

A.2 Message Structure ......................................................................................................................................A–1

A.2.1 Start Character.......................................................................................................................................A–2

A.2.2 Device Address......................................................................................................................................A–2

A.2.3 Command/Responses.............................................................................................................................A–3

A.2.4 End Character........................................................................................................................................A–3

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A.3 Configuration Commands/Responses .......................................................................................................A–4

A.3.1 Modulator Configuration Commands/Responses..................................................................................A–4

A.3.1.1 Prime Modulator Active.................................................................................................................A–4

A.3.1.2 BackupModulator Active...............................................................................................................A–4

A.3.2 Demodulator Configuration Commands/Responses..............................................................................A–4

A.3.2.1 Prime Demodulator Active.............................................................................................................A–4

A.3.2.2 Prime Demodulator Transponder...................................................................................................A–5

A.3.2.3 Backup Demodulator Active..........................................................................................................A–5

A.3.3 Modem Configuration Commands/Responses.......................................................................................A–5

A.3.3.1 Prime Modem Address...................................................................................................................A–5

A.3.3.2 Backup Modem Address................................................................................................................A–6

A.3.3.3 Prime Modem Interface Type.........................................................................................................A–6

A.3.3.4 Backup Modem Interface Type......................................................................................................A–6

A.3.3.5 Modem Priority..............................................................................................................................A–7

A.3.3.6 Modem Online Delay.....................................................................................................................A–7

A.3.4 Status Commands/Responses.................................................................................................................A–7

A.3.4.1 Configuration Status....................................................................................................................... A–7

A.3.4.1.1 Prime Modulator Configuration Status...................................................................................A–7

A.3.4.1.2 Backup Modulator Configuration Status ................................................................................A–8

A.3.4.1.3 Prime Demodulator Configuration Status...............................................................................A–8

A.3.4.1.4 Backup Demodulator Configuration Status............................................................................A–8

A.3.4.2 Modulator Status............................................................................................................................A–9

A.3.4.3 Demodulator Status........................................................................................................................A–9

A.3.4.4 Prime Modem Fault Status.............................................................................................................A–9

A.3.4.5 Backup Modem Fault Status ........................................................................................................A–10

A.3.4.6 Firmware Version Status.............................................................................................................. A–10

A.3.4.7 Equipment Type...........................................................................................................................A–10

A.3.5 Operational Commands.......................................................................................................................A–10

A.3.5.1 Time of Day.................................................................................................................................A–10

A.3.5.2 Date..............................................................................................................................................A–11

A.3.5.3 Mode Command...........................................................................................................................A–11

A.3.5.4 Set Backup Modem Online/Offline..............................................................................................A–11

A.3.5.5 Load Modem Configuration(s).....................................................................................................A–12

A.3.5.5.1 Load All Active Modems Configurations.............................................................................A–12

A.3.5.5.2 Load Prime Modem Configuration....................................................................................... A–12

A.3.5.5.3 Load Backup Modem Configuration ....................................................................................A–13

A.3.5.6 Verify Modem Configuration(s)...................................................................................................A–13

A.3.5.6.1 Verify All Active Modems Configurations...........................................................................A–13

A.3.5.6.2 Verify Prime Modem Configuration .....................................................................................A–14

A.3.5.6.3 Verify Backup Modem Configuration..................................................................................A–14

A.3.5.7 Operational Status Commands (Faults)........................................................................................A–14

A.3.5.7.1 Modulator Operational Faults Status....................................................................................A–14

A.3.5.7.2 Demodulator Operational Faults Status................................................................................A–14

A.3.5.7.3 M:N Switch Fault Status Summary.......................................................................................A–15

A.3.5.7.4 Missing Parameter Faults...................................................................................................... A–15

A.3.5.7.5 Bulk Consolidated Status Faults...........................................................................................A–16

A.3.5.8 Downlink Transponder Option.....................................................................................................A–21

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APPENDIX B. REMOTE CONTROL OPERATION: INDEPENDENT MOD/DEMODB–1

B.1 General.........................................................................................................................................................B–1

B.2 Message Structure.......................................................................................................................................B–1

B.2.1 Start Character.......................................................................................................................................B–2

B.2.2 Device Address......................................................................................................................................B–2

B.2.3 Command/Responses .............................................................................................................................B–3

B.2.4 End Character........................................................................................................................................B–3

B.3 Configuration Commands/Responses........................................................................................................B–4

B.3.1 Modulator Configuration Commands/Responses ..................................................................................B–4

B.3.1.1 Prime Modulator Active.................................................................................................................B–4

B.3.1.2 Prime Modulator Priority............................................................................................................... B–4

B.3.1.3 Prime Modulator Online Delay.......................................................................................... ............B–4

B.3.1.4 Backup Modulator Active..............................................................................................................B–5

B.3.2 Demodulator Configuration Commands/Responses ..............................................................................B–5

B.3.2.1 Prime Demodulator Active.............................................................................................................B–5

B.3.2.2 Prime Demodulator Priority...........................................................................................................B–5

B.3.2.3 Prime Demodulator Transponder...................................................................................................B–6

B.3.2.4 Prime Demodulator Online Delay..................................................................................................B–6

B.3.2.5 Backup Demodulator Active..........................................................................................................B–6

B.3.3 Modem Configuration Commands/Responses.......................................................................................B–7

B.3.3.1 Prime Modem Address...................................................................................................................B–7

B.3.3.2 Backup Modem Address................................................................................................................B–7

B.3.3.3 Prime Modem Interface Type.........................................................................................................B–7

B.3.3.4 Backup Modem Interface Type......................................................................................................B–8

B.3.4 Status Commands/Responses.................................................................................................................B–8

B.3.4.1 Configuration Status.......................................................................................................................B–8

B.3.4.1.1 Prime Modulator Configuration Status ...................................................................................B–8

B.3.4.1.2 Backup Modulator Configuration Status................................................................................. B–8

B.3.4.1.3 Prime Demodulator Configuration Status...............................................................................B–9

B.3.4.1.4 Backup Demodulator Configuration Status.............................................................................B–9

B.3.4.2 Modulator Status............................................................................................................................B–9

B.3.4.3 Demodulator Status......................................................................................................................B–10

B.3.4.4 Prime Modem Fault Status...........................................................................................................B–10

B.3.4.5 Backup Modem Fault Status........................................................................................................B–10

B.3.4.6 Firmware Version Status..............................................................................................................B–10

B.3.4.7 Equipment Type...........................................................................................................................B–11

B.3.5 Operational Commands .......................................................................................................................B–11

B.3.5.1 Time of Day.................................................................................................................................B–11

B.3.5.2 Date..............................................................................................................................................B–11

B.3.5.3 Mode Command...........................................................................................................................B–12

B.3.5.4 Set Backup Modulator Online/Offline.......................................................................................... B–12

B.3.5.5 Set Backup Demodulator Online/Offline .....................................................................................B–12

B.3.5.6 Load Modem Configuration(s)..................................................................................................... B–13

B.3.5.6.1 Load All Active Modems Configurations.............................................................................B–13

B.3.5.6.2 Load Prime Modem Configuration.......................................................................................B –13

B.3.5.6.3 Load Backup Modem Configuration.....................................................................................B–14

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B.3.5.7 Verify Modem Configuration(s)...................................................................................................B–14

B.3.5.7.1 Verify All Active Modems Configurations...........................................................................B–14

B.3.5.7.2 Verify Prime Modem Configuration.....................................................................................B–15

B.3.5.7.3 Verify Backup Modem Configuration ..................................................................................B–15

B.3.5.8 Operational Status Commands (Faults)........................................................................................B–15

B.3.5.8.1 Modulator Operational Faults Status ....................................................................................B–15

B.3.5.8.2 Demodulator Operational Faults Status................................................................................B–15

B.3.5.8.3 M:N Switch Fault Status Summary....................................................................................... B–16

B.3.5.8.4 Missing Parameter Faults......................................................................................................B–16

B.3.5.8.5 Bulk Consolidated Status Faults...........................................................................................B–17

B.3.5.9 Downlink Transponder Option.....................................................................................................B–22

APPENDIX C. 7 DOWNLINK OPTION..................................................................... C–1

C.1 External Connections .................................................................................................................................C–2

C.1.1 D/L Switch Input (J7) ............................................................................................................................C–2

C.1.2 D/L Switch Output (J16)........................................................................................................................C–2

C.1.3 Downlink Inputs (J8 through J10, J12 through J15) ..............................................................................C–3

C.1.4 Backup Demod (J11).............................................................................................................................C–3

C.2 Front Panel Operation ...............................................................................................................................C–3

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xii MN/SMS758 Rev. 3

1.1 Scope

This manual describes the SMS-758 modem protection switch (Figure 1-1), hereafter called “the switch.”

The switch is a rack-mounted unit that provides independent backup control for modulators and demodulators, or simultaneous modulator and demodulator (modem) switching.

If a primary modem element failure occurs, the switch limits the loss of communication.

1.2 Purpose and Function

Chapter 1.

INTRODUCTION

The switch is a fully automated, self-contained switching unit for many EFData satellite data modems, including:

• SDM-650B

• SDM-308B

• SDM-309B

• SDM-8000

• SDM-100

• SLM-4650

• SLM-8650

The switch, with one or two backup modems, provides redundancy for up to eight primary modems.

The switch will automatically or manually switch one of two backup modulators online to take the place of any of eight primary modulators. Also, one of two backup demodulators may be switched online to receive any one of four possible downlinks.

MN/SMS758 Rev. 3 1–1

Introduction SMS-758 Modem Protection Switch

The switch does not contain an IF signal combining/dividing section, so that the user may externally tailor each application for minimum loss. An example system configuration using four prime modems is shown in Figure 1-6.

In normal operation, each prime modulator input is fed through to its corresponding IF output, and the backup modulators are fed to the offline IF outputs. When a modulator fault is detected, the faulted modulator is switched offline and re-routed to one of the offline IF outputs. The next available backup modulator is configured identically to the failed modulator, and is switched ON in its place.

Figure 1-2 shows the switch interface between the prime and backup modems, the terminal equipment, and IF converter equipment. The switch provides:

• All data and IF switching circuitry

• Complete status and fault reporting

The switch provides a high degree of flexibility by utilizing the multiple data rate feature of the modems, and dual backups. Automatic configuration greatly reduces setup time.

1.3 Description

The switch is complete and self contained, in a standard 19” rack-mountable enclosure weighing approximately 50 lbs. It is of modular construction. The chassis assembly is segmented with upper and lower chassis mounted backplanes.

The top section (Figure 1-3) contains:

The lower section contains:

The switch contains a microcontroller system. This system controls all switching functions and maintains communication with the modems. It also communicates with an optional external controller. A remote operator can control the switching by using a terminal or computer, and the remote serial interface.

• Two power supplies providing redundancy in case of power failure, four printed

circuit board (PCB) assemblies, and the front panel keypad and display, which are accessible from the front of the switch.

• Serial remote interfaces, relay-remote/fault, modulator and demodulator status,

and IF connections accessible from the rear panel. Figure 1-4 is a block diagram of the IF switching matrix.

• An enclosed storage area, accessible from the front panel.

• The data switch interface modules, accessible from the rear.

1–2 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Introduction

Redundant power supplies maintain switch operation even if one power supply fails. The switch and modem configurations are stored in battery-backed memory devices, for protection against power loss.

A block diagram of the switch is shown in Figure 1-5.

SMS-758 MO DEM PRO TECTION SWITCH SW1.00 PRESS NE XT

SMS-758

M:N SW ITC H

POWER AUTO LOCAL REMOTE BYPASS

BATTERY

DEMOD

FAULTSSTATUS

MOD

M:N

Figure 1-1. SMS-758 Modem Protection Switch

F1 8

NXT

PRV

9 6

ENT

MN/SMS758 Rev. 3 1–3

Introduction SMS-758 Modem Protection Switch

Figure 1-2. System Block Diagram

1–4 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Introduction

SLOT 1

POWER SUPPLY

NOT USED

SLOT 3

SWITCH DRIVER

SLOT 2

SLOT 4

ADDRESS DEC/DRV

SLOT 5

MONITOR AND CONTROL

SLOT 6

ONLINE TELEMETRY

POWER SUPPLY 2

SLOT 7

Figure 1-3. SMS-758 Upper Front Section Interior

MN/SMS758 Rev. 3 1–5

Introduction SMS-758 Modem Protection Switch

UTS

INPUTS

BU MOD 2 BU MOD 1

MOD 1

MOD 2

MOD 3

MOD 4

MOD 5

MOD 6

MODULATOR SWITCH

OUTPUTS

IF 1

IF 2

IF 3

IF 4

IF 5

IF 6

DEMODULATOR SWITCH

INP

DOWNLINK 4

DOWNLINK 3

DOWNLINK 2

DOWNLINK 1

BACKUP DEMOD 1

INPUTS

DOWNLINK 4

DOWNLINK 3

MOD 7

MOD 8

IF 7

IF 8

BACKUP 2 IF OUTPUT BACKUP 1 IF OUTPUT

DOWNLINK 2

DOWNLINK 1

Figure 1-4. SMS-758 IF Switching Matrix

BACKUP DEMOD 2

1–6 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Introduction

Figure 1-5. SMS-758 Block Diagram

MN/SMS758 Rev. 3 1–7

Introduction SMS-758 Modem Protection Switch

UPLINK 1

UPLINK 2

DOWNLINK 1

DOWNLINK 2

1:6

SPLITTER

12345

J28

J29

J30

OFF-LINE

IF OUTPUTS

J17 J27

J31

SMS-758

MODULATOR

J18

J19

J20

J21

12345

J32

J33

J34

J35

INPUTS

SWITCH

J22

J23

J24

BACKUP MOD

J26 J36

J25

1:6

SPLITTER

INPUTS

DOWNLINK

BACKUP

DEMODS

DL1

J11 1

DL2

SMS-758

J16 2

DL3J9

DL1

DL2

DL3

DL4

J12

J13

J14

J10

J15

DEMOD

SWITCH

PRIME MOD INPUTS IF OUTPUTS

MUST BE TERMINATED INTO 75 OHMS.

TX IF

RX IF

TX IF

RX IF

TX IF

RX IF

TX IF

PRIME MODEMS

J2J2J2

A1A2A3

INPUTS

J2J2J2

A5A6A7A8A9

A10

RX IF

TX IF

RX IF

TX IF

BACKUP MODEMS

RX IF

NOTE: ALL UNUSED IF SWITCHING CONNECTIONS

PRIME MODEM

DATA

SWITCH

SMS-758

A5A6A7

J1J1J1

TERR DATA

A1A2A3

J1J1J1

TERMINAL

EQUIPMENT

Figure 1-6. Example System Configuration

1–8 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Introduction

The switch consists of the following assemblies:

Assembly D escription Drawing No.

Chassis AS/1890 Controller Motherboard AS/1317 Data Switch Motherboard AS/1349 Monitor and Control AS/0356 Address Decoder/Driver AS/1048 Switch Driver AS/1316 IF Switch AS/1314 O/L Telemetry AS/0585 Display/Keypad AS/0540 Power Supply (2 each) AS/0584 DS-1 Prime Interface Switch AS/0893 8 Optional DS-1 Backup Interface Switch AS/0894 2 Optional V.35 Prime Interface Switch AS/0891 8 Optional V.35 Backup Interface Switch AS/0892 2 Optional RS-422 Prime Interface Switch AS/0890 8 Optional RS-422 Backup Interface Switch AS/0899 2 Optional IDR Prime Interface Switch (1:N) AS/0895 8 Optional IDR Backup Interface Switch (1:N) AS/0896 1 Optional IDR 45MB Prime Interface Switch AS/0936 8 Optional IBS/ASYNC Prime Interface Switch AS/1695 8 Optional IBS/ASYNC Backup Interface Switch AS/1694 2 Optional IDR Prime Interface Switch (2:N) AS/1877-1 8 Optional IDR Backup Interface Switch (2:N) AS/1879 2 Optional Drop & Insert daisy chain Interface Switch AS/1877-2 9 Optional

MN/SMS758 Rev. 3 1–9

Introduction SMS-758 Modem Protection Switch

1.4 Performance Specification

The operating specifications of the switch are described in Table 1-1.

Table 1-1. SMS-758 Performance Specification

Operation

Number of Online Modems Expandable from 1 to 8 with plug-in prime

interface switch modules (the modems can be of different data rates and interfaces, as long as the backup modems are compatible).

Number of Backup Modems Expandable from 1 to 2 with plug-in backup

interface switch modules (IDR AS/0895 interface limits the backup to one).

Data Interfaces DS-1 and G.703, V.35, RS-422/449/

MIL-STD-188-114, IBS, IDR, or D&I. IF Frequency Response 50 MHz to 180 MHz . Downlinks Each demodulator is configurable for 1 of 4 or

7 downlink connections. Uplinks Eight modulator outputs may be externally

combined/divided for any number of uplinks. Prime Modulator to Output Loss Less than 1 dB. Backup Modulator to Prime Output Loss Less than 1 dB. Manual Delay Switch-Over T ime:

Modulator Demodulator

Auto Delay Switch-Over Time:

Modulator Demodulator

Switch-Over Priority One of three priority levels av ailable

Remote Control Interfaces:

External control

Modem Control

Batteries M&C: NiCad, 30 day memory retention.

0 to 127.5 sec., in 0.5 sec. steps.

< 1 sec.

< 3 sweep periods of the back-up

demodulator.

independently for each modulator and

demodulator, if independent mod/demod

firmware is used. Modulators and

demodulators will switch simultaneously with

modem switch firmware.

RS-485 or RS-232C. Baud rates from 110 to

9600, Even or Odd parity, Addresses from

1 to 255.

RS-485, Baud rate 9600, Even parity,

Addresses from 1 to 255.

48 hr. charge time.

1–10 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Introduction

Indicators:

Front Panel LEDs

48-character display

Alarm Reporting:

Controller Fault Alarm

System Fault Alarm

Demodulator Fault Alarm

Operational Modes Auto, Local, Remote, and Bypass. Controls Complete control of all M:N functions from the

Input Voltage 90 to 264 VAC (self-adjusting). Line Power 40W maximum when both power supplies are Line Frequency 47 to 63 Hz.

Size 19" W x 22" D x 12.20" H. Weight 50 lbs.

Power supply on, controller and power supply

alarm, demodulator system failure, modulator

system failure, low battery alarm, auto mode,

local mode, remote mode, and bypass mode.

Prime and backup modulator and

demodulator status (fault and online status),

active modulators and demodulators (prime

and backup), modem address, modem

interface, modem uplink and downlink,

priority, delay, configuration, and fault menus.

Form C relay contact to indicate controller or

power supply failure.

Form C relay contact to indicate any non-

catastrophic failure.

Form C relay contact to indicate all

demodulators faulted and a probable IF loss.

front panel, or through the remote interface.

General

-48 VDC optional.

operating.

MN/SMS758 Rev. 3 1–11

Introduction SMS-758 Modem Protection Switch

This page is intentionally left blank.

1–12 MN/SMS758 Rev. 3

This chapter consists of:

CAUTION

2.1 Unpacking

The switch and manual are packaged in pre-formed, reusable, cardboard cartons containing foam spacing for maximum shipping protection. To remove the switch:

Chapter 2.

INSTALLATION

• Unpacking instructions

• System installation

• System requirements

• Description of the external connections

The equipment contains parts and assemblies sensitive to damage by

Electrostatic Discharge (ESD). Use ESD precautionary procedures when touching, removing, or inserting printed circuit boards.

Do not use any cutting tool that will extend more than 1” into the container

CAUTION

MN/SMS758 Rev. 3 2–1

and cause damage to the modem.

1. Cut the tape at the top of the carton (indicated by OPEN THIS END).

2. Remove the cardboard/foam space covering the switch.

3. Remove the switch, manual, and power cord from carton.

4. Save the packing material for storage or reshipment purposes.

5. Inspect the equipment for any possible damage incurred during shipment.

6. Check the equipment against the packing list to ensure the shipment is correct.

7. Refer to Section 2.2 for further system installation instructions.

Installation SMS-758 Modem Protection Switch

2.2 System Installation

2.2.1 Switch Setup

After unpacking, refer to the following steps to install the switch:

1. Mount the switch chassis in the assigned position of the equipment rack. It is recommended that the switch be supported by a rack-mounted shelf.

2. Be sure that all interface switch modules are in their proper positions, and are fully seated in the rear backplane.

3. Connect the cables to the proper locations on the rear panel. Refer to Section 2.4 for connector pinouts, placement, and function.

4. Open the front panel and verify that the two power supplies and four circuit modules are properly seated in the upper backplane.

5. Before turning the power switch ON, become familiar with front panel operation in Chapter 3.

6. Turn ON each power supply, located inside the front panel. The power switch is ON when the switch is depressed toward the “1”, or when the red side of the switch is exposed.

7. Close the front panel, and configure the switch as described in Section 3.2. Place the switch in the proper mode for operation.

8. If any installation problems occur, refer to Chapter 5 for troubleshooting the system.

2–2 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Installation

2.2.2 Modem Setup

J28 through J35 are the eight IF outputs available to connect to the customer-supplied uplink power combiners.

J7 through J10, and J12 through J15, are the downlink inputs available for use with up to eight customer-supplied downlink splitters. The following steps describe the uplink and downlink connections:

1. Connect the IF output cables 1 through 8 to the appropriate customer-furnished uplink signal combiner inputs.

2. Connect the downlink input cables 1 through 4, or 1 through 7, to the appropriate customer-furnished downlink splitters.

3. When using the 7 downlink option, connect J16 (backup 2 output) to J7, and specify 7 downlinks/1 backup in the System menu.

Note: Be sure to terminate all unused IF outputs and downlink inputs with the supplied 75

2.3 System Requirements

The switch, with all interface assemblies installed (Figure 2-1), is capable of operating as a 2:8 protection switch. This means that two full-duplex standby modems back up eight full-duplex primary modems.

Note: When IDR interface AS/0895 is used, only one backup is available.

The switch can be configured in any combination including:

• TX only modems.

• RX only modems.

• Mixed interfaces (limited to two).

• Multiple uplinks (limited to eight).

• Multiple downlinks (limited to four with 2 backups, 7 with 1 backup).

• Multiple data rate and code rate operation.

• Refer to Section 3.2 for a complete explanation of the configuration function.

BNC terminations.

Ω

MN/SMS758 Rev. 3 2–3

Installation SMS-758 Modem Protection Switch

2.4 External Connections

All connections between the switch and other equipment are made through rear panel connections. Table 2-1 lists these connectors, and Figure 2-1 shows the locations. The uses of these connectors are described in the following sections.

D/L SW IN

DOWN

LINK

INPUTS

OUT

D/L SW

J12

J13

FOR SEVEN DOWNLINK

J14

J15

J16J11

OPERATION

J10

BU DMD OUT

RS485

RS232

RS485

90-264 VAC

EXTERNAL

J1 J2

MODEM

CONTROL

J37

INPUTSJ8

J10

BACK-UP 1

DEMODS

J11

A2 A3

DOWN

LINK

J12

J13

J14

J15

J16

PRIME INTERFACE SWITCH MODULES

J17

OFF-LINE

IF OUTPUTS

J27

Figure 2-1. SMS-758 Rear Panel

123

J28 J29 J30

MOD

ON-LINE STATUS

A6 A7

J20J19J18

321

PRIME MOD INPUTS

IF OUTPUTS

456

J31 J32

DEMOD

ON-LINE STATUS

J5 J6

J22J21

REMOTE/FAULT

J23

J24

654

J33 J34 J35

J38

BACKUP INTERFACE SWITCH MODULES

J39

J25

BACKUP

MOD INP UTS

A10A9

GND

J26

J36

2–4 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Installation

Table 2-1. Rear Panel Connections

Name Ref. Desig. Connector Function

DATA I/O A1 - A10

J1, J2

EXTERNAL

RS485

RS232 MODEM CONTROL RS485 ON-LINE STATUS J4 and J5 25-Pin D Mod and Demod Online Status

REMOTE/FAULT S J6 25-Pin D Relay/Remote and Faults DOWNLINK INPUTS BACK-UP DEMODS PRIME MOD INPUTS BACK-UP MOD INPUTS OFF-LINE IF OUTPUTS IF OUTPUTS J28 through J35 BNC IF Outputs to Uplinks AC POWER J37, J38 CEE22 AC Power Input DC POWER J37, J38 Terminal

GROUND J39 #10-32 Stud Chassis Ground

J1 J2 J3 9-Pin D Remote Interface

J7 through J10, J12 through J15 J11 through J16 BNC Downlink Outputs to Backup

J18 through J25 BNC Modulator IF Inputs J26 and J36 BNC Backup Mod IF Inputs J17 and J27 BNC Offline Mod IF O utputs

37-Pin D 34-Pin Block

15-Pin D 37-Pin D 50-Pin D 50-Pin D

9-Pin D 9-Pin D

BNC Downlink IF Inputs

Block

RS-422/449 and MIL-STD-188-114 I/O V.35 I/O DS-1 and G.703 I/O DCTN I/O IDR I/O IBS I/O Remote Interface

Reporting

Demods

48 VDC Power Input

Note: All unused BNC connectors must have a 75

termination.

Ω

2.4.1 Data I/O

Connect the Modem and Terrestrial Data I/O to the plug-in interface switch modules in the lower rear section of the switch. The interface switch module slots are designated A1 through A10 (left to right, viewed from the rear). A1 through A8 are slots for prime interface switch modules 1 through 8. A9 and A10 are backup module slots 1 and 2.

Prime interface switch modules have two connectors: J1 on the top connects to terrestrial equipment; J2 on the bottom connects to the prime modem. (See Note below.) Backup interface switch modules have one connector, J1, for backup modem connection. Refer to Section 4.3 for electrical specifications, and data pin-outs.

Note: For the RS-422/449/MIL-STD-188-114 interface switch modules: J1 on the left connects to the prime modem, and J2 on the right connects to the terrestrial equipment.

MN/SMS758 Rev. 3 2–5

Installation SMS-758 Modem Protection Switch

2.4.2 External RS485 and RS232 Interface (J1 and J2)

The external interface connectors provide serial remote interface to the switch. An external controller can connect through J1 (RS-485) or J2 (RS-232C).

Use M&C module switch pack SP1 switch 5 (SP1-5) to configure each switch for external remote interface type, either RS-485 or RS-232C. The ON position (nearer the PCB) selects RS-232C interface, and OFF selects RS-485.

The external interface connectors are 9-pin female D connectors with screw locks for mechanical security. The remote connector is a DCE interface.

RS-485 RS-232C

Pin Number Name Pin Number Name

1GND1 2 2 RD (RX) 33TD (TX) 4+RX/TX4 5RX/TX5GND 66 77 8+RX/TX8 9-RX/TX9

2.4.3 Modem Control RS485

The prime and backup modems connect to the switch through J3, the modem control interface connector. This connector provides the bus-type control interface required for system operation.

Refer to Sections 4.2.2, 4.2.3, and the remote specifications (Appendixes A and B) for a complete explanation of the remote interface functions.

Refer to the RS-485 pinout listed in Section 2.4.2

2–6 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Installation

2.4.4 On-Line Status (J4, J5)

Connectors J4 and J5 provide the output for the modulator and demodulator backup online status in form C format:

• J4 is for the modulator online status.

• J5 is for the demodulator online status.

Refer to Section 4.1.7 for a complete explanation of the online status functions.

Two 25-pin female D connectors interface with the online status reporting sections. Screw locks provide mechanical security for the mating connector.

ON-LINE STATUS INTERFACE

Pin #

1 Mod 1 COM Demod 1 COM 2 Mod 1 NC Demod 1 NC 3 Mod 1 NO Demod 1 NO 4 Mod 2 COM Demod 2 COM 5 Mod 2 NC Demod 2 NC 6 Mod 2 NO Demod 2 NO 7 Mod 3 COM Demod 3 COM 8 Mod 3 NC Demod 3 NC

9 Mod 3 NO Demod 3 NO 10 Mod 4 COM Demod 4 COM 11 Mod 4 NC Demod 4 NC 12 Mod 4 NO Demod 4 N O 13 Mod 5 COM Demod 5 COM 14 Mod 5 NC Demod 5 NC 15 Mod 5 NO Demod 5 N O 16 Mod 6 COM Demod 6 COM 17 Mod 6 NC Demod 6 NC 18 Mod 6 NO Demod 6 N O 19 Mod 7 COM Demod 7 COM 20 Mod 7 NC Demod 7 NC 21 Mod 7 NO Demod 7 N O 22 Mod 8 COM Demod 8 COM 23 Mod 8 NC Demod 8 NC 24 Mod 8 NO Demod 8 N O 25 GROUND GROUND

Name

MN/SMS758 Rev. 3 2–7

Installation SMS-758 Modem Protection Switch

2.4.5 Relay-Remote/Fault (J6)

This 25 pin connector provides both input and output signals. The inputs are contact closures or logic-level remote control inputs. The outputs are form C relay contact closures for controller fault, M:N fault, and demodulator system fault.

Refer to Sections 3.2.4, 3.2.5, and 4.3 for more information on the relay-remote and fault functions.

The relay-remote input and fault status interface connects through a 25-pin female D connector. Screw locks provide mechanical security for the mating connector.

Relay-Remote Input and Fault Output Interface

Pin No. Name

1 Controller Fault COM 2 Controller Fault NC 3 Controller Fault NO 4 Relay-Remote Input 0 5 Relay-Remote Input 1 6 Relay-Remote Input 2 7 Relay-Remote Input 3 8 Demodulator Fault COM

9 Demodulator Fault NC 10 Demodulator Fault NO 11 M:N Fault COM 12 M:N Fault NC 13 M:N Fault NO

14 through 24 No Connection

25 Ground

2.4.6 Downlink Inputs (J7 through J10, J12 through J15)

These are the downlink input connectors. These connections provide the inputs to the downlink switching matrix:

• J7 through J10 are the inputs to backup modem 1.

• J12 through J15 are the inputs to backup modem 2, when the switch is

configured for 4 downlinks/2 backups.

Up to seven downlinks can be connected to the switch in the 7 downlink/1 backup configuration. This option is available in the System menu on the front panel.

Downlink inputs that are not being used must be terminated into 75

Refer to Appendix C for more information on the 7 downlink/1 backup option.

2–8 MN/SMS758 Rev. 3

Ω.

SMS-758 Modem Protection Switch Installation

2.4.7 Back-up Demods (J11, J16)

J11 and J16 provide the outputs from the downlink switching matrix. J11 is the backup demod 1 output, and J16 is the backup demod 2 output. They connect to the backup modem’s RX IF inputs.

Any of the 4 downlinks can be directed internally to J11 and J16. The default setting is downlink 1.

The input frequency range is 50 to 180 MHz, with an input impedance of 75

Terminate any back-up demod port into 75

2.4.8 Prime Mod Inputs (J18 through J25)

J18 through J25 are the prime modulator IF input connections to the Modulator IF switching matrix. They connect to the prime modem IF outputs.

The input frequency range is 50 to 180 MHz, with an input impedance of 75

Prime mod inputs that are not being used must be terminated into 75

2.4.9 Back-up Mod Inputs (J26, J36)

J26 and J36 are the backup modulator IF input connectors. They connect to the backup modem IF outputs.

The input frequency range is 50 to 180 MHz, with an input impedance of 75

2.4.10 Offline IF Outputs (J17, J27)

when not being used.

Ω

The offline IF output connectors, J17 and J27 are used as a monitor and test point:

• The outputs of the backup modulators are routed here when not in use.

• When backups are online, the offline primes are routed here.

MN/SMS758 Rev. 3 2–9

Installation SMS-758 Modem Protection Switch

2.4.11 IF Outputs (J28 through J35)

J28 through J35 are the modulator IF switching matrix output connections. They connect to the external uplink power combiners. Up to 8 uplinks can be connected to the switch, or as few as 1.

During normal operation, the prime modulator IF outputs are switched here. During a fault condition, the backup modulator’s IF output will be switched here.

The frequency range is 50 to 180 MHz, with an output impedance of 75 output power level is equal to the modem TX output level, which is from -5 dBm to

-30 dBm.

Any IF outputs that are not being used must be terminated into 75

2.4.12 AC Power (J37, J38)

Two independent, non-locking, 3-prong power cords connect AC power to the two power supplies.

Normal input voltage is 90 to 264 VAC (self-adjusting) at 47 to 63 Hz. Maximum power consumption is 40W.

It is recommended that each power supply be plugged into a different power source, to provide continuous power to the switch if one source fails.

2.4.13 DC Power (J37, J38)

Two terminal blocks are provided for optional -48 VDC (± 4.8V) power supplies. Customer supplied power wires should be fitted with standard #6 screw lugs.

. The typical

Ω

Maximum power consumption is 40W.

It is recommended that each power supply be plugged into a different power source, to provide continuous power to the switch if one source fails.

Note: Applying incorrect input voltage to these connectors can cause severe damage to the switch and will void the product warranty. Verify that the source voltage is correct before connecting the switch.

2.4.14 Ground (J37)

A #10-32 stud is available on the rear panel for connecting the chassis to ground.

2–10 MN/SMS758 Rev. 3

3.1 Front Panel Description

The switch front panel (Figure 3-1) provides the local interface to configure, operate, and monitor the switch:

• A 48-character, 2-line LCD display in the upper-front panel displays options and

status for the operator.

• Nine LEDs grouped under the LCD display provide mode and fault status at a

glance.

• A 16-key keypad to the right allows the operator to perform setup, configuration,

and operation functions.

Chapter 3.

OPERATION

• An audible beeper signals the pressing of a keypad key.

The display, LEDs, and beeper are mapped into address space of the external bus structure. The display updates every second, and the LEDs and beeper update as needed.

SMS-758

M:N SWI TCH

SMS-758 MODEM P R OTECTION SWIT CH SWX.XX PRESS NEXT

POWER AUTO LOCAL REMOTE BYPASS

STATUS

BATTERY

DEMOD

FAULTS

MOD

M:N

F1 F2

7 4

5 2

1 0

ENT

Figure 3-1. SMS-758 Front Panel

MN/SMS758 Rev. 3 3–1

Operation SMS-758 Modem Protection Switch

Any keypad activity provides an interrupt to the processor, which then scans the keypad. After the input has been recognized, the processor takes the appropriate action.

All switch functions are accessible to the operator from the front panel through the [F1] and [F2] keys, the [PREV] key, and the [NEXT] key.

Proper operation of the switch depends on its proper configuration and setup. The following sections describe the front panel and its operation in detail.

3.1.1 LED Indicators

Nine LEDs on the front panel indicate the general switch status and summary fault information, as follows:

Faults

M:N Red LED Lights if M:N fault condition occurs. MOD Red LED Lights if a modulator operation fault occurs. DEMOD Red LED Lights if demodulator operation fault occurs. BATTERY Red LED Lights if the M&C battery voltage is low.

POWER ON Green LED Lights when power is applied to the switch. AUTO Green LED Lights when the switch is in the automatic operating mode. LOCAL Green LED Lights when the switch is in the local operating mode. REMOTE Green LED Lights when the switch is in the remote operating mode. BYPASS Green LED Lights when the switch is in the bypass operating mode.

3.1.2 Keypad and LCD Display

The keypad and LCD display provide an interface for the local operator to access the menus that configure and operate the switch. The keypad includes the following keys:

• Numbers 0 through 9

• Decimal

• [ENT] key

• [F1] and [F2] keys

• [NEXT] and [PREV] keys

The [F1], [F2], [NEXT], and [PREV] keys control the hierarchical menu structure. Menus provide for local setup, configuration, and operation.

Each menu contains a portion of the switch control, or setup algorithm.

Status

Only a limited knowledge of the switch is required, as the menus are self-prompting, and all options are displayed.

3–2 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Operation

The base levels of this tree-structured front panel menu are as follows:

• ID menu displayed at power-on

• SYSTEM and MODEM SETUP menu

• CONFIGURATION and VERIFICATION menu

• FAULT menu

• MODE menu

• STATUS display

The ID menu displays the model number of the switch and version of firmware installed.

The [NEXT], [PREV], [F1], [F2], and [ENT] keys control the menus, and allow menu selections.

Some display messages have menu options on the right side, aligned with the [F1] and [F2] keys. Pressing either of those keys directs the display to the selected menu.

The operator can move forward or backward through the selected menu by pressing the [NEXT] or [PREV] keys.

The switch beeps in response to keypad inputs:

• One beep acknowledges a valid entry, with the appropriate action being taken.

• Two beeps indicate that the entry was invalid, and no action was taken.

Once the correct menu is selected, the operator can press the [ENT] key to enter, change, or view the functions within that menu.

Refer to Figure 3-2 for details of the menu hierarchy and display s.

The display maps show the menus available with independant mod/demod firmware installed (version 6.x.x). Modem switching firmware (version 5.x.x) has slight differences in the “Modem Setup” and “Local Mode” menus.

In the “Modem Setup” menu:

• The “Select Interface” menu with the options 7, 8, and 9 does not exist.

• “Mod Priority” and “Demod Priority” are conbined into “Modem Priority.”

• “Demod Delay” and “Mod Delay” are combined into “Modem Delay.”

In the “Local Mode” menu,

• The “Select Mod or Demod” menu does not exist.

MN/SMS758 Rev. 3 3–3

Operation SMS-758 Modem Protection Switch

Figure 3-2. SMS-758 Display Map (Sheet 1 of 2)

3–4 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Operation

Figure 3-2. SMS-758 Display Map (Sheet 2 of 2)

MN/SMS758 Rev. 3 3–5

Operation SMS-758 Modem Protection Switch

3.2 Switch Setup

3.2.1 System Setup

Enter the SYSTEM SETUP menu to enter, change, or view the system setup configuration. The definitions of the system setup functions are as follows:

TIME AND DATE Time and date are entered and displayed. DOWNLINK OPTION Downlink options are entered and displayed. (Refer to Appendix C.) PRIME MODS Active prime modulators are selected and displayed. PRIME DEMODS Active prime demodulators are selected and displayed. BACKUP MODS Active backup modulators are selected and displayed. BACKUP DEMODS Active backup demodulators are selected and displayed. MODEM ADDRESSES Prime and backup modem addresses are selected and displayed.

In the SYSTEM SETUP menu, the operator views system configuration parameters by using the [NEXT] and [PREV] keys. The operator can also enter data or change a parameter through keypad entries.

When all data or changes for that parameter are entered correctly, press [ENT] to load the information into memory.

After [ENT] is pressed, the display will increment to show the next available menu. If an incorrect entry is made, press [PREV] to return to that menu, and re-enter the data.

The following sections describe each parameter in detail.

3.2.1.1 Time and Date Menu

This menu displays the current time and date. The operator can enter the time by pressing [F1] and following the format:

HH MM

[F1] should then be pressed to select AM, or [F2] for PM.

When [ENT] is pressed, seconds reset to 0, and the new time loads into the clock device.

The operator can enter the date by pressing [F2] and following the format:

MM DD YY

Pressing [ENT] loads the new date into the clock device.

3–6 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Operation

3.2.1.2 Downlink Option

This menu displays the current downlink option, showing how many downlinks and backups are selected.

The operator may choose from four downlinks with two backups possible, or seven downlinks and only one backup. Pressing any number key will toggle the two options, and pressing [ENT] will load the displayed choice into memory.

Refer to Appendix C for more information about the 7 downlink/1 backup option.

3.2.1.3 Active Prime Modulators Menu

This menu displays the current prime modulators that are active in the system. Pressing the keys [1] through [8] will toggle the active status (ON/OFF) of the corresponding modulator only. Modulators with numbers displayed are active. Pressing [ENT] loads that information into memory.

3.2.1.4 Active Prime Demodulators Menu

This menu displays the current prime demodulators that are active in the system. Pressing the keys [1] through [8] will toggle the active status of the corresponding demodulator only. Demodulators with numbers displayed are active. Pressing [ENT] loads that information into memory.

3.2.1.5 Active Backup Modulators Menu

This menu displays the current backup modulators that are active in the system. Pressing the keys [1] or [2] will toggle the active status of the corresponding backup modulator only. Modulators with numbers displayed are active. Pressing [ENT] loads that information into memory.

3.2.1.6 Active Backup Demodulators Menu

This menu displays the current backup demodulators that are active in the system. Pressing the keys [1] or [2] will toggle the active status of the corresponding backup demodulator only. Demodulators with numbers displayed are active. Pressing [ENT] loads that information into memory.

MN/SMS758 Rev. 3 3–7

Operation SMS-758 Modem Protection Switch

3.2.1.7 Modem Addresses Menu

This menu displays the current addresses of the prime and backup modems, and channel units, if applicable. Addresses of 1 through 255 are valid. Entering a new address and pressing [ENT] loads the address into memory. If no address is entered for an active modem, an M:N fault results.

Never use the global address “0”. The configurations of the prime modems

CAUTION

Note: Pressing [ENT] while in this menu will increment the prime modem number, while [NEXT] will transfer the user out of that address subsection to the next menu.

For example, after assigning address 2 to prime modem 2 and pressing [ENT], an address may be assigned to prime modem 3. Pressing [NEXT] then will allow the user to skip prime modems 3 through 8, and go directly to the backup modem menu, and assign an address to backup modem 1.

may become corrupted.

3.2.2 Modem Setup

To enter, change, or view the modem setup configuration, enter the MODEM SETUP menu by pressing F2. The MODEM SETUP functions are as follows:

INTERFACE Interface type is selected and displayed for each modem. DOWNLINK Downlink assignment (1 through 4, or 1 through 7) is selected and

MOD PRIORITY The prime modulator priorities are selected and displayed. DEMOD PRIORIT Y The prime demodulator priorities are selected and displayed. DEMOD DELAY The prime demodulator online delay is selected and displayed. MOD DELAY The prime modulator online delay is selected and displayed.

Note: When using modem switch firmware, mod and demod priorities are combined into modem priority, and mod and demod delays are combined into modem delay, since the mod and demod switch simultaneously.

In the MODEM SETUP menu, the operator can select prime or backup modems by pressing [F1] or [F2]. It is recommended that the prime modems be configured first, since the switch increments the number of the prime modem displayed as each previous set of parameters is entered.

For example, after configuring prime modem 1, the switch will ask for the configuration for prime modem 2, etc.

displayed for demodulators. (Refer to Appendix C.)

3–8 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Operation

The operator can view the modem configuration parameters by using the [NEXT] and [PREV] keys. A flashing cursor will be displayed over the selected parameter. To enter data or change a parameter, the operator uses the keypad to enter the data. When all data or changes for that parameter are correct, press [ENT] to load the information into memory. The following sections describe each parameter in detail.

Note: [ENT] or [NEXT] may be used to get from one frame to the next in this menu, but only [ENT] will enter data.

3.2.2.1 Interface Type Menu

This menu displays the current interface type for each prime and backup modem. Selections 1 through 9 are labeled:

Screen 1 1. 15D (For both DS-1 and G.703 interfaces)

2. V.35

3. RS449 (For both RS-422/449 and M IL-ST D -188-114/R S-449 interfaces)

Screen 2 4. DCTN (Modified RS-422 interface)

5. IDR (for 1:N AS/0895)

6. OTHER

Screen 3 7. IBS

8. D&I (for “loomed” D&I systems. Read paragraph below.)

9. IDR 2:N (for 2:N AS/1877)

The operator enters the number associated with the interface type, and presses [ENT] to load the selected interface information into memory. Selections may only be made from the displayed options. If no interface type is entered for an active modem, an M:N fault results.

The OTHER interface type applies to ASYNC interfaces (AS/1695), or installations with dual 1:4 systems, or similar configurations having identical interfaces. Normally, the switch treats the two 1:4 systems with the same interface type as a single 2:8, but when OTHER interface type is selected for one of the 1:4 systems, the switch considers the interfaces different, and treats each 1:4 system as a separate system.

The “loomed” D&I system requires special firmware in the switch, special switch interfaces (AS/2152), additional breakout panels, and special cabling. The advantage of the “loomed” system is that during switching, there is no interruption of the data stream (T1 or E1). The only data that is affected is the data of the failed unit.

Note: Interface type is the only setup parameter for backup modems.

Note: Although the last three options do not exist with modem switch firmware, IBS and

IDR 2:N can be chosen by selecting option 6 (OTHER).

MN/SMS758 Rev. 3 3–9

Operation SMS-758 Modem Protection Switch

3.2.2.2 Downlink Selection Menu

This menu displays the current downlink number (1 through 4, or 1 through 7) for each demodulator. When the operator enters the number of the downlink selected and presses [ENT], that information is loaded into memory. If no downlink is selected for an active demodulator, an M:N fault results.

Note: Hardware connections for uplink and downlink must be identical to the setup selection. Any difference causes erroneous switch operation.

Refer to Appendix C for more information about the 7 downlink/1 backup option.

3.2.2.3 Modulator Priority Menu

This menu displays the current priority level for this prime modulator.

• “1” indicates high priority.

• “2” indicates medium priority.

• “3” indicates low priority.

When the operator enters “1”, “2”, or “3” and presses [ENT], the information is loaded into memory. If nothing is entered, the priority will be low.

The backup algorithm uses priority levels to make backup decisions. When a backup modulator is online for a faulted prime with a lower priority than a newly faulted modulator, that backup modem becomes available for use to backup the newly faulted unit having the higher priority.

3.2.2.4 Demodulator Priority Menu

This menu displays the current priority level for this prime demodulator.

• “1” indicates high priority.

• “2” indicates medium priority.

• “3” indicates low priority.

When the operator enters “1”, “2”, or “3” and presses [ENT], the information is loaded into memory. If nothing is entered, the priority will be low.

The backup algorithm uses priority levels to make backup decisions. When a backup demodulator is online for a faulted prime with a lower priority than a newly faulted prime, that backup modem becomes available for use to backup the newly faulted unit having the higher priority.

3–10 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Operation

3.2.2.5 Demodulator Delay

This menu displays the current online delay for this prime demodulator, and allows the operator to enter a new parameter. The DEMOD DELAY is the time allowed for the prime demodulator to clear its faulted state. At the end of this delay, if the prime is no longer faulted, it will be restored to online status. If the prime is still faulted, the backup demodulator is committed to that channel and will be unavailable for any other faulted prime having the same or lower priority.

The operator selects “1”, “2”, or “3”:

• “1” for no time delay.

• “2” for manual.

• “3” for automatic delay selection (2 times the sweep period).

Entering “1” or “3” and pressing [ENT] loads the information into memory. Entering “2” and pressing [ENT] allows the operator to enter from 0 to 127.5 seconds, in 0.5 second increments. When [ENT] is pressed again, the delay data is loaded into memory.

If nothing is entered, the switch automatically defaults to “3” (automatic).

3.2.2.6 Modulator Delay

The Modulator Delay menu displays the current online delay for this prime modulator, and allows the operator to enter a new parameter. The MOD DELAY is the time allowed for the prime modulator to clear its faulted state. At the end of this delay, if the prime is no longer faulted, it is restored to online status. If the prime is still faulted, the backup modulator is committed to that channel, and will be unavailable for any other faulted prime having the same or lower priority.

The operator selects “1” or “2”:

• “1” for no time delay.

• “2” for manual.

Entering “1” and pressing [ENT] loads the information into memory. Entering “2” and pressing [ENT] allows the operator to enter from 0 to 127.5 seconds, in 0.5 second increments. When [ENT] is pressed again, the delay data is loaded into memory.

If nothing is entered, the switch defaults to 1 (none).

Note: In certain applications, the MOD/DEMOD DELAY and PRIORITY settings are replaced by MODEM DELAY and PRIORITY settings. This occurs when modem switch firmware is used instead of independent mod/demod.

MN/SMS758 Rev. 3 3–11

Operation SMS-758 Modem Protection Switch

3.2.3 Modem Configuration

3.2.3.1 Prime and Backup Modem Configuration

The operator must be sure that the prime modems have all parameters properly configured for operation prior to configuration loading or verifying. The only required parameters for a backup modem are the data rate and code rate assignments in the modem’s utility menu.

To communicate with the modems, the switch must have the modem addresses entered into the system configuration. The serial interface type, baud rate, and parity of the switch modem control interface is fixed, and therefore cannot be programmed by the operator. For interface information, refer to Section 4.1.5.

The modems must be set to RS-485 interface, 9600 baud, and even parity. Each modem in the switch system must have its own unique address. The interface type, baud rate, parity, and addresses are selected on the M&C card in the modem. (See the appropriate section of the modem installation and operation manual.)

3.2.3.2 Modem Configuration Menu

To load the modem configurations, press [F1] (LOAD) in the MODEM CONFIGURATION menu, and proceed as follows:

1. To load the configuration of an individual prime or backup modem, use the [F1] (SELECT) menu. If [F1] (SELECT) is pressed, the menu presents options of PRIME (F1) and BACKUP (F2). After the selection of prime or backup, the last menu will require entry of the prime or backup modem number. The switch automatically loads the configuration of the modem selected.

2. To load the configuration of all active modems, use the [F2] (ALL) menu. If [F2] (ALL) is pressed, the menu requires that [ENT] be pressed to begin the loading of all active modem configurations.

The switch displays “OK” or “ERROR”, showing the result of the configuration loading process. An “ERROR” response results in an M:N fault.

3–12 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Operation

3.2.3.3 Modem Verification

To verify the modem configurations, press [F2] (VERIFY) in the MODEM CONFIGURATION menu, and proceed as follows:

1. To verify the configuration of an individual prime or backup modem, use the [F1] (SELECT) menu. If F1 (SELECT) is pressed, the menu presents options of PRIME (F1) and BACKUP (F2). After the selection of prime or backup, the last menu will require entry of the prime or backup modem number. The switch automatically verifies the configuration of the modem selected.

2. To verify the configuration of all the active modems, use the [F2] (ALL) menu. If F2 (ALL) is pressed, the menu requires that [ENT] be pressed to begin the verifying of all active modem configurations.

The switch displays “OK” or “ERROR”, showing the result of the configuration loading process. An “ERROR” response results in an M:N fault.

3.2.4 Faults

Note: When any change is made in the prime or backup modem configuration, the operator must reload that modem’s configuration into the switch. If this is not done, a configuration verify error will be flagged in the M:N fault menu.

When any fault LED(s) is lighted, an operational fault condition exists. However, LEDs are only a summary visual alarm. The operator should use the FAULT menu to determine the exact cause of the fault and takes remedial action, if necessary.

The FAULT menu provides fault information. Use the [1], [2], [3], [4], [NEXT], and [PREV] keys to reveal the nature of any fault indicated by a front panel red LED.

The following sections list all possible fault messages that could appear in each category.

Refer to Section 5.2 for a list of possible causes, and for the fault isolation procedures.

3.2.4.1 Modulator Operation Fault

The fault menu displays MOD fault(s) when a modulator backup switching operation failure occurs. The messages will be as follows:

BK-UP FAULT MOD X

(Where: X = 1 to 8.)

MN/SMS758 Rev. 3 3–13

Operation SMS-758 Modem Protection Switch

3.2.4.2 Demodulator Operation Fault

The fault menu displays DEMOD fault(s) when a demodulator backup switching operation failure occurs. The messages will be either of the following:

BK-UP FAULT DMD X

(Where: X = 1 to 8.)

ALL DMDS D/L X FAULTED

(Where: X = 1 to 7.)

3.2.4.3 M:N Faults

The fault menu displays M:N fault(s) when a communication, configuration, setup, and/or power supply failure occurs. The messages will be any of the following:

MODEM X COMM FAILURE MODEM BX COMM FAILURE CONFIG VERIFY ERROR M (or D) X CONFIG VERIFY ERROR BM (or BD) X BK-UP M (or D) X NOT COMPATIBLE PRIME M (or D) X NOT COMPATIBLE NO ADDRESS FOR PRIME X NO ADDRESS FOR BK-UP X NO INTERFACE FOR PRIME X NO INTERFACE FOR BK-UP X NO D/L FOR DMD X NO CONFIG FOR PRIME M (or D) X NO CONFIG FOR BK-UP M (or D) X

(Where X = 1 to 8.) (Where X = 1 to 2.) (Where X = 1 to 8.) (Where X = 1 to 2.) (Where X = 1 to 2.) (Where X = 1 to 8.) (Where X = 1 to 8.) (Where X = 1 to 2.) (Where X = 1 to 8.) (Where X = 1 to 2.) (Where X = 1 to 8.) (Where X = 1 to 8.) (Where X = 1 to 2.)

+12V FAILURE

-12V FAILURE

+5V FAILURE POWER SUPPLY 1 FAULT POWER SUPPLY 2 FAULT

3.2.4.4 Battery Faults

The fault menu displays a BATTERY fault when an M&C battery failure (low voltage) occurs in the switch. The message will be as follows:

M&C BATTERY FAULT

3–14 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Operation

3.2.5 Operational Modes

The MODE menu selects the mode of operation. At power-up, the switch defaults to the BYPASS mode unless:

• It was in a different mode prior to loss of power.

• The battery-backed memory was maintained.

The following modes of operation are available:

BYPASS All switching is halted. No change will take place until the switch is returned to

the AUTO, LOCAL, or REM OTE mode. No interruptions will occur in the data

flow of any modem already backed-up as a result of changing modes. AUTOMATI C The M&C controls all switching. LOCAL The on-site operator controls all switching. REMOTE In REMOTE mode, all sw itching is controlled by a remote controller v ia the

remote interface. The on-site operator cannot select this mode of operation.

3.2.5.1 Bypass Mode

The BYPASS mode is recommended for configuration functions. It is the default operating mode at power-up, if the switch was not programmed for a different mode prior to loss of power, or if the battery-backed memory was not maintained. The switch is not capable of performing any switching functions in the BYPASS mode. All configuration and communication functions continue to operate, but no new backup operation can take place. Any backup operation performed prior to selecting BYPASS will remain in effect.

To enter the BYPASS mode, press [3] + [ENT] while in the MODE menu.

3.2.5.2 Auto Mode

The AUTO mode is the normal operating mode for the switch. Refer to the flowcharts in Figures 3-3 and 3-4. If the switch was in this mode when power loss occurred, it will return to this mode when power is restored. All previous backup status will be lost, but if there are faults present when power is restored, the switch will backup those faulted modulators and/or demodulators accordingly. Because the switch is communicating with the prime and backup modems in this mode, response to keypad input and remote communication may be delayed.

To enter the AUTO mode, press [1] + [ENT] while in the MODE menu.

MN/SMS758 Rev. 3 3–15

Operation SMS-758 Modem Protection Switch

In the AUTO mode, the switch monitors the prime and backup modulator and demodulator fault inputs, awaiting a failure. When no faults are present, the switch will place the backup modulator(s) and demodulator(s) in the “Hot Standby” mode for the highest priority prime(s), and a dash (-) will be displayed in the status display. In this mode, the switch programs the backup modulator(s) and demodulator(s) for the highest priority, lowest numbered prime modulator(s) and demodulator(s), and connects the downlink IF to the backup demodulator(s). This action prepares the backup modulator(s) and demodulator(s) for a minimal delay during the backing up of high priority channels.

When a fault does occur, the switch takes action according to the backup algorithm. The backup algorithm selects the highest priority, lowest numbered faulted channel for backup, and will take a lower priority channel backup offline, even if that channel is still faulted, to back up a higher priority channel.

When a demodulator backup is required, the switch performs the following steps:

1. It verifies the configuration of the backup demodulator, and re-programs it, if necessary.

2. If more than one demodulator is faulted, the switch selects the demodulator with the highest priority. If more than one faulted demodulator is set to the highest priority, the switch selects the demodulator with the lowest channel number.

3. The switch implements the sweep delay (it is not programmable by the user). This delay is two times the sweep period of the demodulator. At the end of the sweep delay or when the backup demodulator locks, the switch performs one of the following operations:

a. If the backup demodulator fails to lock, the switch makes the back-up

demodulator available for other faulted channels.

b. If the backup demodulator locks, the switch commits the backup

demodulator to the faulted prime and starts the demodulator delay timer. An asterisk (*) will be displayed in the status display if modem switch firmware is installed. (Continue to Step 4.)

4. At the end of the demodulator delay, the switch again checks the fault status of the prime demodulator.

a. If the prime demodulator still shows a fault, the switch places the backup

demodulator online for the faulted prime, and an arrow will be displayed in the status display. The backup will then be available only to failed primes having higher priority.

b. If the prime demodulator locks during the demodulator delay, the backup

demodulator is made available for other faulted primes.

3–16 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Operation

When a modulator backup is required, the switch performs the following steps:

1. It verifies the configuration of the backup modulator and re-programs it, if necessary.

2. If more than one modulator is faulted, the switch selects the modulator with the highest priority. If two or more faulted modulators are set to the highest priority, the switch selects the modulator with the lowest channel number.

3. It implements a 500 millisecond delay (not programmable by the user). At the end of the delay, the switch performs one of the following operations:

a. If the prime modulator is not faulted, the switch makes the backup modulator

available for other faulted channels.

b. If the backup modulator is not faulted, and the prime remains faulted, the

switch commits the backup modulator to the faulted prime, and starts the modulator delay timer. An asterisk (*) is displayed in the status display if modem switch firmware is used. (Continue to Step 4.)

4. At the end of the modulator delay, the switch again checks the fault status of the prime modulator.

a. If the prime modulator is still faulted, the switch places the backup

modulator online for the faulted prime, and an arrow is displayed in the status display. The backup is then available only to failed primes having higher priority.

b. If the prime modulator clears its fault during the modulator delay, the prime

modulator is restored to service. The backup modulator is made available for other faulted primes.

When a modem backup is required, the switch performs both demodulator and modulator procedures simultaneously. However, the switch will not place the backup modem online until the backup demodulator locks and the modem online delay timer times-out.

The switch continually verifies the configurations of all active modulators and demodulators. If the switch fails to verify any configuration, an M:N fault results.

Changing from any mode to another mode (including AUTO) does not change the backup status unless a new fault occurs.

MN/SMS758 Rev. 3 3–17

Operation SMS-758 Modem Protection Switch

DEMOD AUTO MODE

YES

HAS THE

VERIFY TIMER

TIMED OUT?

ARE ANY

PRIMES

FLT’D?

YES

ARE THE

FLT’D

PRIMES

B/U’D?

PUT FLT’D PRIMES IN PRIORITY ORDER. START WITH

HIGHEST PRIORITY.

IS THIS

FLT’D

PRIME B/U’D?

IS A B/U

AVAILABLE?

YES

THE B/U

ON STAND-BY

FOR THIS

PRIME?

YES

VERIFY B/U

CONFIGURATION.

UPDATE IF

NECESSARY. (SERIAL REMOTE NOT AVAILABLE)

YES

OF THE NEXT DMD.

PROGRAM B/U (s) FOR HIGHES T PRIORITY CHANNEL( s). (SERIAL REMOTE NOT AVAILABLE)

YES

PRIOIRTY PRIME

CONFIGURATION FOR THIS PRIME. (SERIAL REMOTE

NOT AVAILABLE)

VERIFY THE

CONFIGURATION (SERIAL REMOTE

NOT AVAILABLE)

ARE THE B/U (s) ON

STAND-BY?

IS A

LOWER

B/U’D?

YES

PROGRAM B/U

WITH THE

YES

PLACE B/U (s ) IN STAND-BY MODE. INDICATE WITH “-” ON FRONT PANEL

IS A

NON-FLT’D

PRIME B/U’D?

YES

WAIT FOR ALL

YES

APPLICABLE TIMERS.

YES

FLT’D PRIME IN THE

YES

INDICATE PRIME

WITH “#” ON

FRONT PANEL

GO TO NEXT

PRIORITY ORDER.

ARE ALL

PRIME DMDS

FLT’D?

SET THE DMD

OPERATION FLT.

(FRONT PANEL

LEDS.)

YES

IS THE

PRIME STILL

FLT’D?

YES

PLACE B/U ON - LINE

FOR FLT’D PRIME. INDICATED PRIME

WITH “->“ ON

FRONT PANEL.

SET ALL DMDS

FLT’D FLT. (BACK

PANEL RELAY)

IS THE

B/U DMD

FLT’D?

HAS THE

SWEEP TIMER

TIMED OUT?

YES

ARE OTHER PRIMES

FLT’D?

ARE

ANY

FLT’D PRIMES

NOT B/U’D?

Figure 3-3. SMS-758 Switching Algorithm Flow Chart

(Demodulator and Modem)

3–18 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Operation

MOD AUTO MODE

YES

HAS THE

VERIFY TIMER

TIMED OUT?

ARE ANY PRIMES

FLT’D?

YES

ARE THE

FLT’D

PRIMES

B/U’D?

PUT FLT’D

PRIMES IN PRIORITY ORDER. START WITH

HIGHEST PRIORITY.

IS THIS

FLT’D

PRIME B/U’D?

IS A

B/U

AVAILABLE?

YES

THE B/U

ON STAND-BY

FOR THIS

PRIME?

YES

VERIFY B/U

CONFIGURATION.

UPDATE IF

NECESSARY.

(SERIAL REMOTE

NOT AVAILABLE)

YES

OF THE NEXT MOD.

PROGRAM B/U (s) FOR HIGH ES T PRIORITY CHANNEL(s). (SERIAL REMOTE NOT AVAILABLE)

YES

PRIOIRTY PRIME

PROGRAM B/U

CONFIGURATION

FOR THIS PRIME.

(SERIAL REMOTE

NOT AVAILABLE)

VERIFY THE

CONFIGURATION (SERIAL REMOTE

NOT AVAILABLE)

ARE THE

B/U (s) ON

STAND-BY?

IS A

LOWER

B/U’D?

YES

WITH THE

YES

PLACE B/U (s) IN STAND-BY MODE. INDICATE WITH “-” ON FRONT PANEL

IS A

NON-FLT’D

PRIME B/U’D?

YES

WAIT FOR ALL

APPLICABLE TIMERS.

YES

FLT’D PRIME IN THE

INDICATE PRIME

WITH “#” ON

FRONT PANEL

GO TO NEXT

PRIORITY ORDER.

IS THE

PRIME STILL

FLT’D?

YES

PLACE B/U ON-LINE

FOR FLT’D PRIM E

WITH “->“ ON

FRONT PANEL.

HAS THE ONLINE DELAY TIMER TIMED OUT

YES

IS THE

B/U MOD

FLT’D?

YES

HAS

THE 500 ms

TIMER TIMED

OUT?

YES

ARE

OTHER

PRIMES

FLT’D?

Figure 3-4. SMS-758 Switching Algorithm Flow Chart (Modulator)

MN/SMS758 Rev. 3 3–19

Operation SMS-758 Modem Protection Switch

3.2.5.3 Local Mode

In this operating mode, the switch responds to keypad input affecting setup, configuration, fault inquiries, and backup online status. If the switch is in this mode when power loss occurs, it will return to this mode when power is restored. However, the current backup status will be lost. This mode can also be used for configuration functions.

To enter the LOCAL mode, press [2] + [ENT] while in the MODE menu.

To change the backup status from local mode, proceed as follows:

1. Press [F1] or [F2] to select modulator or demodulator. (If the switch is a modem switch rather than an independent modulator/demodulator switch, press [ENT] to continue.)

2. Select the backup modem number (“1” or “2”), and press [ENT].

3. Select the prime modem number from 0 to 8. (“0” takes the backup modulator or demodulator offline. “1” to “8” selects that prime for backup.) Press [ENT].

The switch performs the selected function and displays the online and fault status. When the switch is in LOCAL mode, exercise care when changing the online status. The switch performs the selected function regardless of fault status or modulator and demodulator compatibility.

3.2.5.4 Remote Mode

In this operating mode, the switch responds to serial remote interface or relay-remote input. The switch can receive a full range of commands from the serial remote interface user, and a limited number from the relay-remote interface. If the switch was in this mode prior to loss of power, it returns to this mode when power is restored. However, current backup status will be lost.

This mode can be entered only from the serial remote interface or relay-remote interface.

For details of the Remote Interface Specification, refer to Sections 4.2 and 4.3, and Appendixes A and B.

3–20 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Operation

3.2.6 Status Menu

The STATUS display follows the MODE menu. It provides the following inform ation:

• I dentifies the activ e modulators and demodulators, both prime and backup.

• Shows backup online status.

• Shows the fault status of all active prime and backup modulators and

demodulators.

The STATUS menu displays only the active modulators and dem odulators. If any modulator or demodulator is faulted, an “F” alternates with the modem number on the display.

The display shows online backup modulators and demodulators, with an arrow pointing to the number of the prime being back ed- up.

“Hot Standby” mode is identified by a dash between the backup modulator/demodulator and the prime modulator/demodulator.

An asterisk is displayed while the backup modulator/demodulator is in the process of backing up a prime m odulator/dem odulator if modem switch firmware is installed (5.x.x).

In all modes except BYPA SS , the STATUS display returns after approximately three minutes without keypad activity .

Refer to Figure 3-2 for details of the menu hierarchy and display s.

MN/SMS758 Rev. 3 3–21

Operation SMS-758 Modem Protection Switch

This page is intentionally left blank.

3–22 MN/SMS758 Rev. 3

THEORY OF OPERATION

4.1 Monitor and Control

A sophisticated microcontroller performs the monitor and control functions of the switch. The module, called the “Monitor and Control” (M&C), plugs into slot 5 of the switch chassis (refer to Figure 4-1 for a drawing of the M&C, and Figure 1-3 for the location in the chassis).

The M&C gathers status and provides extensive fault monitoring. The M&C monitors the switch configuration and updates other modules within the switch, as required. Switch configuration parameters are stored in battery-backed RAM to provide total recovery after a power-down.

A local front panel interface and a remote communications interface provide user access to all switch functions.

Chapter 4.

SWITCH PACK (SP1)

PARITY AND BAUD RATE

SWITCH PACK (SP2)

ADDRESS

Figure 4-1. Monitor and Control

MN/SMS758 Rev. 3 4–1

JUMPERS JP1 THROUGH JPX

Theory of Operation SMS-758 Modem Protection Switch

4.1.1 Theory of Operation

The M&C module uses an Intel 80C31 microcontroller operating at 5.5295 MHz.

The microsystem supports:

• 128K bytes of Read-Only Memory (ROM) for code.

• 64K bytes of Random-Access Memory (RAM) for data.

Of the 64K bytes, only 8K is used for RAM, and the remaining 56K is used for memorymapped I/O.

Memory-mapped I/O includes:

• Real time clock/memory.

• 8-channel analog-to-digital converter.

• External buffered bus structure for overall switch control and status gathering.

The 80C31 microcontroller supports a serial asynchronous communications channel (RS-232C), with a maximum baud rate of 9600 bit/s using the 5.5295 MHz reference.

A rechargeable battery maintains the system real time clock and switch configuration through power-down situations. Memory is maintained up to 30 days without power. A full battery charge is attained after the switch is powered ON for 48 hours.

4.1.2 M&C Serial Interface

The M&C communicates with the address decoder/driver through an RS-232C interface.

To set the M&C for RS-232C operation:

1. Remove JP1, JP2, and JP3. Install JP4, JP5, and JPX.

2. Install JP7 at RS-232 location.

Note: The M&C should always be set up this way, even when using external RS-485 communications.

4–2 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

4.1.3 Remote Baud Rate

The eight position switch pack, SP1, on the M&C module programs the external remote serial communications baud rate and parity. Set the switches to ON (nearer the PCB) or OFF (away from the PCB) to select parity and baud rate.

SP1 switch position 1 (SP1-1) sets the parity:

• “OFF” for even parity

• “ON” for odd parity

SP1 switch positions 2, 3, and 4 (SP1-2, SP1-3, and SP1-4) set the baud rate as follows:

Baud SP1-2 SP1-3 SP1-4

110 ON ON ON 150 ON ON OFF 300 ON OFF ON 600 ON OFF OFF

1200 OFF ON ON 2400 OFF ON OFF 4800 OFF OFF ON 9600 OFF OFF OFF

4.1.4 Remote Address

The switch connects to an RS-485 remote communication link. To communicate on this link, each unit must have a unique address between 1 and 255. (0 cannot be a device address, as it is the global address for all devices.) To set an address, use the 8-position switch pack, SP2, on the M&C module.

Addresses are binary coded numbers:

• Switch position 1 (SP2-1) is the most significant bit.

• Switch position 8 (SP2-8) is the least significant bit.

To turn ON any switch, move it to the position closer to the PCB. For example:

Address SP2-1 SP2-2 SP2-3 SP2-4 SP2-5 SP2-6 SP2-7 SP2-8

1 OFF OFF OFF OFF OFF OFF OFF ON 3 OFF OFF OFF OFF OFF OFF ON ON 5 OFF OFF OFF OFF OFF ON OFF ON

9 OFF OFF OFF OFF ON OFF OFF ON 17 OFF OFF OFF ON OFF OFF OFF ON 33 OFF OFF ON OFF OFF OFF OFF ON 65 OFF ON OFF OFF OFF OFF OFF ON

129 ON OFF OFF OFF OFF OFF OFF ON 255 ON ON ON ON ON ON ON ON

MN/SMS758 Rev. 3 4–3

Theory of Operation SMS-758 Modem Protection Switch

4.1.5 External Remote Serial Interface Selection

An RS-485 or RS-232C communications link on the address decoder/driver module provides remote serial interface for all switch functions.

The RS-485 interface allows up to 32 devices to operate on a common communication link. Each device must have a discrete address (there are 255 available discrete addresses). RS-232C communication is only possible with a single device. Before the configuration setup, the M&C is jumpered for RS-232C communication, but the switch will still communicate via RS-485. See Figure 4-1 for locations of the switches and jumpers.

4.1.6 Battery

A rechargeable battery on the M&C module allows it to retain configuration and status information for up to 30 days without prime power. M&C module jumper JP6 connects battery power from the backup RAM. During normal operation, this jumper should be in the ON position. Refer to Figure 4-1 for jumper location. Should the switch be powered down, the M&C microcontroller performs the following sequence:

1. Upon power-up, the M&C microcontroller checks the battery-backed RAM for valid data. If valid data has been retained, the M&C implements the RAM-stored switch configuration.

2. If the battery-backed RAM fails the valid data test, the switch defaults to the bypass mode, and no configuration is loaded.

To clear the memory, JP6 must be set OFF, and the leads of capacitor C12 must be shorted. JP6 must then be set ON again, so the memory can retain a new configuration.

Note: The external battery option (JP8) is not supported in the SMS-758 chassis, and must be OFF.

4.1.7 Error Response Function

This is a switch function for indicating an error message when a command cannot be carried out because local processing is using the modem control bus, local keyboard control, and so forth.

4–4 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

The functions for the error response switches, SW1-6, -7, and -8 are described in Table 4-1. Table 4-2 lists the different software versions required for each switch function.

MN/SMS758 Rev. 3 4–5

Theory of Operation SMS-758 Modem Protection Switch

Table 4-1. Error Response Switch Options

Switch

Position

SP1-6 ER6_BUSY enable

SP1-7 ER6_BUSY wait

SP1-8 WAIT for Modem response

Switch Function Description

Selects whether the switch will return an ON = Enabled OFF = Disabled

ON = Immediate response OFF = 2 second response

ON = 2 seconds OFF = 4 seconds

ER6_BUSY response if it cannot process the

received remote command. A response will not

be returned if this switch is OFF.

Selects the time the switch attempts to process

the command. ER6_BUSY enable determines if

ER6_BUSY will be returned or not. In the

immediate response mode (ON), this will be less

than 320 ms from the command response

received by the switch.

Selects the time the switch will wait for a modem

to respond to a remote command.

Table 4-2. Software Versions for Response Switch

Software Versions

Switch Function Modem Switch Mod/Demod Switch

ER6_BUSY enable ER6_BUSY wait WAIT for modem response

≥ 5.00 ≥ 6.00 ≥ 5.09 ≥ 6.11 ≥ 5.10 ≥ 6.12

4.1.8 External I/O Interrupt Arbitration

The SMS-758 switch does not use the external I/O interrupt arbitration function. JP12, JP13, and JP14 must be in the “LEFT” position to disable this function.

4.2 Modem Control Interface Specification

The modem control interface is an RS-485 serial communication link which allows the switch to maintain control of backup modems, and verify the configuration of the prime and backup modems. (See Section 2.4.3 for details of connector position and pinout.)

The RS-485 interface permits up to 32 devices to operate on a common communication link. However, only modems and channel units may be connected to this communication link, besides this switch. External remote communication to the modems and switch is accomplished through the external remote interface. Refer to Section 4.1.5 for more information.

The user cannot configure the parameters of the RS-485 interface. The baud is fixed at 9600 and parity is even. All devices communicating with the switch must have their remote control interfaces configured to those parameters. Each modem and channel unit must have a unique address. Refer to the Installation and Operation Manuals for each device for details of remote interface specification and configuration.

4–6 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

4.3 Relay-Remote Interface Specification

This section defines the protocol and word/command structure of the relay-remote interface.

The relay-remote input (J6) allows the user to execute a limited number of mode and online commands (refer to Section 2.4.5 for connector location and pinout). These commands are a series of 4-bit words.

The switch has a 4-line parallel interface with pull-up resistors (10K open inputs are logic high, and logic low inputs can be generated by connecting to pin 25 of J6. The inputs can also be driven directly from TTL or CMOS family devices.

The M:N switch recognizes a word 100 msec after the change of state is detected on the parallel interface. The words must be held for 200 msec, and should not be sent faster than 500 msec, or slower than 10 second intervals.

The word can be repeated any number of times, but the switch only detects it the first time it is sent. The following section describes the commands that can be executed.

4.3.1 Command Structure

A command to the switch consists of three or four words sent on the four parallel lines, in Non-Return-to-Zero (NRZ) or Return-to-Zero (RZ) format.

The switch recognizes each word by changes of state at the relay-remote inputs. After debounce, the switch identifies the word. If all words are valid and the EXECUTE word is received, the switch performs the command.

The command words START and EXECUTE are defined in Table 4-3. Target words are defined in Table 4-4. The six command functions are defined in Table 4-5.

to +5V). Thus,

Ω

A valid command structure consists of words in the following order:

1. The START word begins all messages.

2. The COMMAND word follows the start word.

3. If the command affects the online or offline status of a prime modulator or demodulator, the next 4-bit word must be the TARGET word. The format for the target word is the BCD number for the prime modulator or demodulator. The target word is not sent if the backup is to be taken offline, or AUTO or REMOTE mode is selected.

4. The EXECUTE word follows the target (or command) word.

MN/SMS758 Rev. 3 4–7

Theory of Operation SMS-758 Modem Protection Switch

The command words must be sent to the switch with no more than 10 seconds between words for the switch to recognize a command. If the interval exceeds 10 seconds, the M&C resets the word buffer, and waits for the next START word.

If an incorrect word is sent, begin the message sequence again with the START word. This word restarts the message sequence.

Table 4-6 shows some relay-remote command examples.

Table 4-3. Relay-Remote Command Words

Input Lines

Command Word REM3 REM2 REM1 REM0

START C C C C AUTO N N C N REMOTE N N N C B/U MOD 1 C C N C B/U MOD 2 C C C N B/U DEMOD 1 C N N C B/U DEMOD 2 C N C N EXECUTE C C N N C = Change of state. N = No change of state.

Table 4-4. Modem Target Words

Input Lines

Target Modem REM3 REM2 REM1 REM0

1NNNC 2NNCN 3NNCC 4NCNN 5NCNC 6NCCN 7NCCC 8CNNN

C = Change of state. N = No change of state.

4–8 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

Table 4-5. Relay-Remote Command Functions

Function Description

AUTO Executed only from REMOT E mode. T his function places the switch in

the automatic mode of operation.

REMOTE Executed from any operating mode other than REMO T E; must be

executed before any other relay-remote function. This function places the switch in the remote mode of operation.

BACKUP MOD 1 Executed only from REMO T E mode. This function is used to place

backup modulator 1 online when it precedes a target word, or offline when it precedes EXECUTE.

BACKUP MOD 2 Executed only from REMO T E mode. This function is used to place

backup modulator 2 online when it precedes a target word, or offline when it precedes EXECUTE.

BACKUP DEMOD 1 Executed only from REMOTE mode. This function is used to place

backup demodulator 1 online when it precedes a target word, or offline when it precedes EXECUTE.

BACKUP DEMOD 2 Executed only from REMOTE mode. This function is used to place

backup demodulator 2 online when it precedes a target word, or offline when it precedes EXECUTE.

Table 4-6. Relay-Remote Command Examples

Input Lines

Command Words Rem3 Rem2 Rem1 Rem0 Comments

START CCCCPlaces the M:N in the remote REMOTE NNNCmode. EXECUTE CCNN

START CCCCPlaces B/U modulator 1 online for B/U MOD 1 CCNCprime 2. TARGET PRIME 2NNCN EXECUTE CCNN

START CCCCPlaces B/U modulator 2 online for B/U MOD 2 CCCNprime 6. TARGET PRIME 6NCCN EXECUTE CCNN

START CCCCPlaces B/U demodulator 1 online B/U DEMOD 1 CNNCfor prime 5. TARGET PRIME 5NCNC EXECUTE CCNN

START CCCCPlace B/U demod 2 offline. B/U DEMOD 2 CNCN(No target word.) EXECUTE CCNN

START CCCCPlaces the M:N in the auto mode. AUTO NNCN EXECUTE CCNN C = Change of state. N = No change of state. Mod = Modulator. Demod = Demodulator.

MN/SMS758 Rev. 3 4–9

Theory of Operation SMS-758 Modem Protection Switch

4.4 Fault Interface Specification

This section defines the protocol and format structure for monitoring the fault status interface of the switch.

The relay-remote/fault rear panel connector (J6) provides interface for fault status information. (See Section 2.4.5 for connector location and pin-out information.)

Three non-latching relays with form C contacts show:

• Controller status

• M:N status

• Demodulator signal status

These contacts report summary status. To determine the exact fault, the user must make further inquiry, as described in Section 3.2.4.

4.4.1 Controller fault

A controller fault is a catastrophic failure that renders the switch non-functional. A timer on the M&C periodically sets a monostable multivibrator which controls the fault relay. The controller fault relay NC and COM contacts close when one of the following occurs:

• No power is applied to the switch.

• M&C fails to set the monostable.

During normal operation (when no fault occurs), the relay NC and COM contacts are open, and the NO and COM contacts are closed.

4.4.2 M:N Fault

An M:N fault is any failure of backup operation, communication, configuration, and/or setup that may (or may not) render the switch non-functional.

During normal operation or when power is OFF, the relay is de-energized (COM to NC). When any failure occurs, the relay energizes (COM to NO). It remains energized until the failure is eliminated.

4–10 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

4.4.3 Demodulator Signal Fault

A demodulator signal fault is the failure of all active demodulators on the indicated downlink to acquire and lock to their signals. The fault alarm indicates a possible down converter system failure, causing loss of IF to the demodulators.

During normal operation or power-down, the relay is de-energized (COM to NC). When all demodulators indicate loss of carrier, the relay energizes (COM to NO). The relay remains energized until the failure is eliminated.

4.5 Online Status Specification

This section defines the protocol and format for reporting the online status of the switch.

The M&C commands the online telemetry module to report online status for all active prime modulators and demodulators. The status is reported as form-C relay contacts to the online status connectors (J4 and J5) on the rear panel. (See Section 2.4.4 for connector locations and pinouts.)

4.5.1 Modulator Online Status

The active modulator’s online status is indicated by form-C relay contacts. When the prime is online or power is OFF, the relay is de-energized (COM to NC). When a backup modulator goes online for that prime, the relay energizes (COM to NO).

4.5.2 Demodulator Online Status

The active demodulator’s online status is indicated by form-C relay contacts. When the prime is online or power is OFF, the relay is de-energized (COM to NC). When a backup demodulator is online for that prime, the relay is energized (COM to NO).

MN/SMS758 Rev. 3 4–11

Theory of Operation SMS-758 Modem Protection Switch

4.6 Interface Switches

The prime interface switch module can plug into any prime interface switch module slot (A1 through A8) on the left side of the lower rear panel. The backup interface switch module can plug into A9 or A10 (on the right side).

When the prime interface switch module (or the M:N switch itself) is powered down or in the default position, all signals are routed between the terminal equipment and the prime modem.

Modulator and/or demodulator signals can be independently switched to either of the two backup modem interface switch modules, if the independent mod/demod firmware is used. If modem switch firmware is used, then both the modulator and demodulator switch to the backup when either the prime modulator or demodulator indicates a fault.

4.6.1 RS-422/449 and MIL-STD-188-114/RS-449 Interface Switch

The RS-422/449 and MIL-STD-188-114/RS-449 interface switch module switches all interface signals by relay.

The prime interface switch module (Figure 4-2) has two 37-pin female D connectors.

• Prime modem interface (J1) on the left is a DTE interface.

• Terminal equipment interface (J2) on the right is a DCE interface.

The backup interface switch module (Figure 4-3) has one 37-pin female D connector.

The backup modem interface (J1) is a DTE interface.

A buffered set of transmit clock (TT) and master clock (MC) signals are switched to the “hot standby” backup modulator or demodulator, or to the offline prime modulator and demodulator when a backup operation occurs.

The fault lines from the modem connector are routed through the interface switch modules to the M&C.

4.6.1.1 Specification

Circuits Supported SD, ST, TT, RD, RT, DM , R R, C S, RS, MC. Switching Format Modulator and demodulator signals switch indiv idually with dry

contacts.

Contact Arrangement Modulator signals: 10 poles.

Demodulator signals: 10 poles.

4–12 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

4.6.1.2 Connector Pinouts

A 37-pin female D connector provides interface for the RS-422/449 and MIL-STD-188-114/RS-449 interface.

Screw locks provide mechanical security for the mating connector.

Signal Function Name Pin #

Signal Ground SG 1,19,20,37 Send Data SD-A 4 SD-B 22 Send Timing ST -A 5 ST-B 23 Receive Data RD-A 6 RD-B 24 Request To Send RS-A 7 RS-B 25 Receiver Timing RT-A 8 RT-B 26 Clear To Send CS-A 9 CS-B 27 Data Mode DM-A 11 DM-B 29 Receiver Ready RR-A 13 RR-B 31 Terminal Timing TT-A 17 TT-B 35 Master Clock MC-A 16 MC-B 34 Modulator Fault MF 3 Demodulator Fault DF 21

Note: MF and DF inputs are only on the prime and backup modem interface connectors, not the terrestrial data connector.

MN/SMS758 Rev. 3 4–13

Theory of Operation SMS-758 Modem Protection Switch

TRANSMIT CLOCK

TRANSMIT DATA

RECEIVE DATA

RECEIVE CLOCK

RECEIVE EXTERNAL REFERENCE CLOCK

TERRESTRIAL DATA I/O

RX S/B

TX S/B

TRANSMIT CLOCK

TRANSMIT DATA

RECEIVE DATA

RECEIVE CLOCK

RECEIVE EXTERNAL REFERENCE CLOCK

FAULTS

PRIME C/U DATA I/O

DATA PATH SELECTION

TRANSMIT CLOCK

TRANSMIT DATA

RECEIVE DATA

THE RELAYS ARE SHOWN IN THE NON-ENERGIZED

NOTE:

POSITION CONNECTING THE TERRESTRIAL DATA AND PRIME MODEM CONNECTORS TOGETHER. STANDBY (S/B) SIGNALS ARE ROUTED TO THE OFFLINE BACKUP MODEM.

MOD RELAYS

DEMOD RELAYS

RECEIVE CLOCK

RECEIVE EXTERNAL REFERENCE CLOCK

MOD AND DEMOD FAULTS

INSTRUCTION DECODER

Figure 4-2. Prime RS-422/449 and MIL-STD-188-114/RS-449 Interface Switch

DATA SWITCH MOTHERBOARD

4–14 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

DATA PA TH SELECTION

TRANSMIT CLOCK

TRANSMIT DATA

RECEIVE DATA

RECEIVE CLOCK

RECEIVE EXTERNAL REFERENCE CLOCK

MOD AND DEMOD FAULTS

BACKUP DATA I/O

MOD RELAYS

DEMOD RELAYS

INSTRUCTION

DECODER

DATA SWITCH MOTHERBOARD

Figure 4-3. Backup RS-422/449 and MIL-STD-188-114/RS-449 Interface Switch

MN/SMS758 Rev. 3 4–15

Theory of Operation SMS-758 Modem Protection Switch

4.6.2 V.35 Interface Switch

The V.35 interface switch module switches all interface signals by relay. The prime interface switch module (Figure 4-4) has two 34-pin female block connectors.

• J1 (top) for terminal equipment is a DCE interface.

• J2 (bottom) for prime modem is a DTE interface.

The backup interface switch module (Figure 4-5) has one 34-pin female block connector. The backup modem (J1) is a DTE interface. The prime interface switch module can plug into any interface switch module slot (A1 through A8) on the left side of the lower rear panel. The backup interface switch module can plug into A9 or A10, on the right side.

When the prime interface switch module (or the M:N switch itself) is powered down or in the default position, all signals are routed between the terminal equipment and the prime modem.

A buffered set of transmit clock (SCTE) and master clock (MC) signals is switched to the “hot standby” backup modulator or demodulator, or to the offline prime modulator and demodulator when a backup operation occurs.

The fault lines from the modem connector are routed through the interface switch modules to the M&C.

4.6.2.1 Specification

Circuits Supported SD, SCT, SC T E, R D, SCR , M C , CT S, R T S, DSR , RLSD. Switching Format Modulator and demodulator signals switched individually with dry

contacts.

Contact Arrangement Modulator signals: 8 poles

Demodulator signals: 8 poles

4–16 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

4.6.2.2 Connector Pinouts

The V.35 interface is an industry standard 34-pin block connector.

Screw locks provide mechanical security for the mating connector.

Signal Function Name Pin #

Signal Ground SG A,B Transmit Data SD-A P SD-B S Serial Clock Transmit SCT-A Y SCT-B a (AA) Receive Data RD-A R RD-B T Request To Send RTS C Serial Clock Receive SCR-A V SCR-B X Clear To Send CTS D Data Set Ready D SR E Rcv. Line Signal Det. R LSD F Serial Clock Transmit Ext SCTE-A U SCTE-B W Master Clock MC-A c (CC) MC-B d (DD) Modulator Fault MF m (MM) Demodulator Fault DF n (NN)

Note: MF and DF inputs are only on the prime and backup modem interface connectors, not the terrestrial data connector.

MN/SMS758 Rev. 3 4–17

Theory of Operation SMS-758 Modem Protection Switch

CE CLOC

TRANSMIT CLOCK

TRANSMIT DATA

RECEIVE DATA

RECEIVE CLOCK

RECEIVE EXTERNAL REFERENCE CLOCK

TERRESTRIAL DATA I/O

THE RELAYS ARE SHOWN IN THE NON-ENERGIZED

NOTE:

POSITION CONNECTING THE TERRESTRIAL DATA AND PRIME MODEM CONNECTORS TOGETHER. STANDBY (S/B) SIGNALS ARE ROUTED TO THE OFFLINE BACKUP MODEM.

RX S/B

TX S/B

TRANSMIT CLOCK

MIT DATA

TRAN

RECEIVE DATA

RECEIVE CLOCK

RECEIVE EXTERNAL REFEREN

FAULTS

DATA PATH SELECTION

TRANSMIT CLOCK

TRANSMIT DATA

RECEIVE DATA

RECEIVE CLOCK

RECEIVE EXTERNAL REFERENCE CLOCK

PRIME C/U DATA I/O

MOD AND DEMOD FAULTS

MOD RELAYS

DEMOD RELAYS

INSTRUCTION DECODER

DATA SWITCH MOTHERBOARD

Figure 4-4. Prime V.35 Interface Switch

4–18 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

DATA PA TH SELECTION

TRANSMIT CLOCK

TRANSMIT DATA

RECEIVE DATA

RECEIVE CLOCK

RECEIVE EXTERNAL REFERENCE CLOCK

MOD AND DEMOD FAULTS

BACKUP DATA I/O

MOD RELAYS

DEMOD RELAYS

INSTRUCTION

DECODER

Figure 4-5. Backup V.35 Interface Switch

DATA SWITCH MOTHERBOARD

MN/SMS758 Rev. 3 4–19

Theory of Operation SMS-758 Modem Protection Switch

4.6.3 V.35/RS-232 Interface Switch

The V.35/RS-232 interface switch module switches all interface signals by relay. Interface types can be changed between V.35 and RS-232 by the SPDT toggle switch located on the back of the daughter card. Both the prime and backup interfaces must be in V.35 mode or RS-232 mode in order to operate correctly.

The prime interface switch module (Figure 4-6) has two 25-pin D connectors:

• J1 (top) for terminal equipment is a DCE interface.

• J2 (bottom) for the prime modem is a DTE interface.

The backup interface switch module (Figure 4-7) has one 25-pin D connector. The backup modem (J1) is a DTE interface.

The prime interface switch module can plug into any of the interface switch module slots (A1 through A8) on the left side of the lower rear panel. The backup interface can plug into either A9 or A10.

When the prime interface switch module (or the M:N switch itself) is powered down or in the default position, all signals are routed between the terminal equipment and the prime modem.

A buffered set of transmit clock (SCTE) and master clock (MC) signals is switched to the “hot standby” backup modulator or demodulator, or the offline prime modulator and demodulator when a backup operation occurs.

The fault lines from the modem connector are routed through the interface switch modules to the M&C.

4–20 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

4.6.3.1 Electrical Specifications

V.35

Circuit Supported SD, SCT, SCTE, RD, SCR, DSR, DSR , RLSD Switching Format Modulator and demodulator signals individually

with dry contacts

Contact Arrangement Mod Signals: 8 poles

Demod Signals: 8 poles Amplitude (RD, SCR, SCT, SD, SCTE) 0.55V peak ± 20% differential into 100 Amplitude (CTS, DSR, RLSD) Impedance (RD, SCR, SCT) 100 ± 20 Impedance (SD, SCTE) 100 ± 10 Impedance (RTS) DC Offset (RD, SCR, SCT)

10 ± 5V into 5000 ± 2000

Ω Ω

Ω

5000 ± 2000Ω, < 2500 pF

0.6V max., 1000Ω termination to ground

Polarity (SD, SCT, SCTE, RD, SCR) True when B positive wrt A

False when A positive wrt B Polarity (RTS, SCT, DSR, RLSD)

True when < -3V wrt G ND

False when > +3V wrt GND Phasing (SCTE, SCR) False-to-true transition, nominally in center of data

bit Symmetry (SCR, SCTE, SCT) Frequency

50%, ± 5%

100 PPM

Ω

MN/SMS758 Rev. 3 4–21

Theory of Operation SMS-758 Modem Protection Switch

4.6.3.2 Connector Pinouts

4.6.3.2.1 V.35 Option

The V.35 interface has been converted from the 34-pin block connector (refer to Figure 4-4) to a 25-pin D connector (refer to Figure 4-6) that is accessible from the back panel. Screw locks are provided for mechanical security of the mating connector.

Pin #

(25-Pin)

1 A Ground 7 B Ground 14 P Send D ata A 2 S Send Data B 25 U Serial Clock Transmit External A 24 W Serial Clock Transmit External B 18 Y Serial C lock T r ansmit A 15 a (AA) Serial Clock Transmit B 16 R Receive Data A 3 T Receive Data B 19 V Serial C lock R eceiv e A 17 X Serial C lock R eceiv e B 4 C R equest to Send 5 D C lear to Send 6 E Data Set Ready 8 F Receive Line Signal Detect 22 c (CC) Ex ternal R eference Clock A 23 d (DD) External Reference Clock B 20 m (MM) Modulator fault 21 n (NN) Demodulator fault 9, 10, 11, 12, and 13 No connection in 25-pin

H, J, M, N, Z, b (BB), e (EE), f (FF), h (HH), j (JJ), k (KK), and l (LL)

Pin #

(34-Pin Block)

Signal Name

connector No connection in 34-pin block

4–22 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

4.6.3.2.2 RS-232 Option

When the switch is in the RS-232 position, the 25-pin D connector now provides the interface for RS-232 mode of operation. Screw locks are provided for mechanical security of the mating connector.

Pin # Signal Name Direction Circuit

1 Ground AA 7 Ground AB 2 Transmitted Data IN BA

15 Transmission Signal Element Timing OUT DB

3 Received Data OUT BB 4 Request to Send IN CA

17 Receiver Signal Element Timing OUT DD

5 Clear to Send OUT CB

18 Carrier Present OUT

6 Data Set Ready OUT CC 8 Receive Line Signal Detect OUT CF

9 External Reference Clock IN 11 Demodulator Fault 24 Transmit Signal Element Timing IN DA 25 Modulator Fault

10, 12, 13, 14, 16, 19, 21, 22, 23

No connection

MN/SMS758 Rev. 3 4–23

Theory of Operation SMS-758 Modem Protection Switch

CE CLOC

TRANSMIT CLOCK

TRANSMIT DATA

RECEIVE DATA

RECEIVE CLOCK

RECEIVE EXTERNAL REFERENCE CLOCK

TERRESTRIAL DATA I/O

V.35/RS-232 PRIME INTERFACE SWITCH

THE RELAYS ARE SHOWN IN THE NON-ENERGIZED

NOTE:

POSITION CONNECTING THE TERRESTRIAL DATA AND PRIME MODEM CONNECTORS TOGETHER. STANDBY (S/B) SIGNALS ARE ROUTED TO THE OFFLINE BACKUP MODEM.

RX S/B

TX S/B

TRANSMIT CLOCK

MIT DATA

TRAN

RECEIVE DATA

RECEIVE CLOCK

RECEIVE EXTERNAL REFEREN

FAULTS

DATA PATH SELECTION

TRANSMIT CLOCK

TRANSMIT DATA

RECEIVE DATA

RECEIVE CLOCK

RECEIVE EXTERNAL REFERENCE CLOCK

PRIME C/U DATA I/O

MOD AND DEMOD FAULTS

MOD RELAYS

DEMOD RELAYS

INSTRUCTION DECODER

DATA SWITCH MOTHERBOARD

Figure 4-6. Prime V.35/RS-232 Interface Switch

4–24 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

DATA PA TH SELECTION

TRANSMIT CLOCK

TRANSMIT DATA

RECEIVE DATA

RECEIVE CLOCK

RECEIVE EXTERNAL REFERENCE CLOCK

MOD AND DEMOD FAULTS

BACKUP DATA I/O

MOD RELAYS

DEMOD RELAYS

INSTRUCTION

DECODER

Figure 4-7. Backup V.35/RS-232 Interface Switch

DATA SWITCH MOTHERBOARD

MN/SMS758 Rev. 3 4–25

Theory of Operation SMS-758 Modem Protection Switch

4.6.4 DS-1 and G.703 Interface Switch

The DS-1 and G.703 interface switch module switches all interface signals by relay.

The prime interface switch module (Figure 4-8) that is most commonly used for DS-1 has two 15-pin female D connectors.

• Terminal equipment interface J1 (top) is a DCE interface.

• Prime modem interface J2 (bottom) is a DTE interface.

The backup interface switch module (Figure 4-9) has one 15-pin female D connector. The backup modem interface J1 is a DTE interface.

There are two optional G.703 interfaces with the following connectors:

• Two BNC connectors for SD and RD, each for the prime modem and terrestrial

data connections, and a 15-pin female D connector for modem mod and demod faults. The backup has two BNC connectors for SD and RD, and a 15-pin female D connector for modem mod and demod faults.

• Two 25-pin female D connectors on the prime, and one on the backup.

When the prime interface switch module (or the M:N switch itself) is powered down or in the default position, all signals are routed between the terminal equipment and the prime modem.

A buffered set of transmit data (SD) and master clock (MC) signals is switched to the “hot standby” backup modulator or demodulator, or to the offline prime modulator and demodulator when a backup operation occurs.

The fault lines from the modem connector are routed through the interface switch modules to the M&C.

4–26 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

4.6.4.1 Specification

Circuits Supported SD, RD, MC. Switching Format Modulator and demodulator signals switched individually

with dry contacts.

Contact Arrangement Modulator signals: 2 poles.

Demodulator signals: 4 poles.

4.6.4.2 Connector Pinouts

The DS-1 and G.703 interface uses a 15-pin female D connector accessible from the switch rear panel.

Screw locks provide mechanical security for the mating connector.

Signal Function Name Pin #

Shields - 2,4 Send Data SD-A 1 SD-B 9 Receive Data RD-A 3 RD-B 11 Master Clock MC-A 7 MC-B 8 Modulator Fault MF 14 Demodulator Fault DF 15

Note: MF and DF inputs are only on the prime and backup modem interface connectors, not the terrestrial data connector.

MN/SMS758 Rev. 3 4–27

Theory of Operation SMS-758 Modem Protection Switch

TRANSMIT DATA

RECEIVE DATA

RECEIVE EXTERNAL REFERENCE CLOCK TX S/B

TERRESTRIAL DATA I/O

THE RELAYS ARE SHOWN IN THE NON-ENERGIZED

NOTE:

POSITION CONNECTING THE TERRESTRIAL DATA AND PRIME MODEM CONNECTORS TOGETHER. STANDBY (S/B) SIGNALS ARE ROUTED TO THE OFFLINE BACKUP MODEM.

RX S/B

TRANSMIT DATA

RECEIVE DATA

RECEIVE EXTERNAL REFERENCE CLOCK

MOD AND DEMOD FAULTS

MOD RELAYS

DEMOD RELAYS

TRANSMIT DATA

RECEIVE DATA

RECEIVE EXTERNAL REFERENCE CLOCK

FAULTS

DATA PATH SELECTION

INSTRUCTION DECODER

DATA SWITCH MOTHERBOARD

PRIME C/U DATA I/O

Figure 4-8. Prime DS-1 and G.703 Interface Switch

4–28 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

DATA PATH SELECTION

TRANSMIT DATA

RECEIVE DATA

RECEIVE EXTERNAL REFERENCE CLOCK

MOD AND DEMOD FAULTS

BACKUP DATA I/O

MOD RELAYS

DEMOD RELAYS

INSTRUCTION

DECODER

DATA SWITCH MOTHERBOARD

Figure 4-9. Backup DS-1 and G.703 Interface Switch

MN/SMS758 Rev. 3 4–29

Theory of Operation SMS-758 Modem Protection Switch

4.6.5 IDR Interface Switch

This section covers the 1:N AS/0895 prime and AS/0896 backup interfaces. Refer to Section 4.6.5 for information on the 2:N AS/1877 prime and AS/1879 backup interfaces.

The IDR interface switch module switches all interface signals by relay. The prime interface switch module (Figure 4-10) has two 50-pin female D connectors.

• Terminal equipment interface J1 (top) is a DCE interface.

• Prime modem interface J2 (bottom) is a DTE interface.

The backup interface switch module (Figure 4-11) has one 50-pin female D connector.

The backup modem interface J1 is a DTE interface.

The prime interface switch module can plug into any prime interface switch module slot (A1 through A8) on the left side of the lower rear panel.

Note: The AS/0896 backup interface switch module can only plug into slot A9.

When the prime interface switch module (or the M:N switch itself) is powered down or in the default position, all signals are routed between the terminal equipment and the prime modem.

Modulator and/or demodulator signals can be independently switched to the backup modem interface switch module, if the independent mod/demod firmware is used. If modem switch firmware is used, then both the modulator and demodulator switch to the backup when either the prime modulator or demodulator indicates a fault.

The fault lines from the modem connector are routed through the interface switch modules to the M&C.

Note: The Prime IDR 45MB Interface Switch has buffers for operation from 10 MB to 45 MB.

4–30 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

4.6.5.1 Specification

Circuits Supported SD, RD, EXC, TXD, TX C, TXO, RXD, RXC, R X O , BWO 1-4, BWI

1-4, A1I, A1O, A2I, A2O, AND DEMOD FAULT. Switching Format All signals switched with dry contacts. Contact Arrangement Modulator signals: 16 poles.

Demodulator signals: 26 poles.

Ref. Clock: 2 poles.

Spares: 2 poles.

Demodulator signals: 26 poles.

Ref. Clock: 2 poles.

Spares: 2 poles.

4.6.5.2 Connector Pinouts

The IDR interface uses a 50-pin female D connector.

Screw locks provide mechanical security of the mating connector.

Signal Function Name Pin #

Ground - 1, 2 Send Data SD-A

SD-B

Receive Data RD-A

RD-B

Reference Clock EXC-A

EXC-B

8 KBPS TX Data TXD-A

TXD-B

8 KHz TX Clock Out TXC-A

TXC-B

1 KHz TX Octet In TXO-A

TXO-B

8 KBPS RX Data RXD-A

RXD-B

8 KHz RX Clock Out RXC-A

RXC-B

1 KHz RX Octet Out RXO-A

RXO-B

Backward Alarm 1 Out BWO1-C

BWO1-NC BWO1-NO

Backward Alarm 2 Out BWO2-C

BWO2-NC BWO2-NO

Backward Alarm 3 Out BWO3-C

BWO3-NC BWO3-NO

Backward Alarm 4 Out BWO4-C

BWO4-NC BWO4-NO

34 18 36 20 35 19 37 38 21 22 4 5 39 40 23 24 6 7 8 25 41 9 26 42 10 27 43 11 28 44

MN/SMS758 Rev. 3 4–31

Theory of Operation SMS-758 Modem Protection Switch

Backward Alarm 1 In BWI1 12 Backward Alarm 2 In BWI2 13 Backward Alarm 3 In BWI3 14 Backward Alarm 4 In BWI4 15 ADPCM 1 Audio In A1I-A

A1I-B

ADPCM 1 Audio Out A1O-A

A1O-B

ADPCM 2 Audio In A2I-A

A2I-B

ADPCM 2 Audio Out A2O-A

A2O-B

Demod Fault Relay DF-C

DF-NO Modulator Fault MF 49 Demodulator Fault DF 33 Deferred Maintenance Alarm DMA 17

45 29 46 30 47 31 48 32 16 50

Note: MF and DF inputs are only on the prime and backup modem interface connectors, not on the terrestrial data connector.

4–32 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

CE CLOC

TRANSMIT DATA

TRANSMIT ESC

RECEIVE DATA

RECEIVE ESC

RECEIVE EXTERNAL REFEREN

TERRESTRIAL DATA I/O

NOTE:

THE RELAYS ARE SHOWN IN THE NON-ENERGIZED

POSITION CONNECTING THE TERRESTRIAL DATA AND PRIME MODEM CONNECTORS TOGETHER. STANDBY (S/B) SIGNALS ARE ROUTED TO THE OFFLINE BACKUP MODEM.

RX S/B

TX S/B

MOD RELAYS

DEMOD RELAYS

TRANSMIT DATA

RECEIVE DATA

RECEIVE ESC

RECEIVE EXTERNAL

FAULTS

PRIME C/U DATA I/O

TRANSMIT DATA

TRANSMIT ESC

RECEIVE DATA

RECEIVE ESC RECEIVE EXTERNAL

REFERENCE CLOCK

MOD AND DEMOD FAULTS

INSTRUCTION DECODER

DATA SWITCH MOTHERBOARD

Figure 4-10. Prime IDR Interface Switch

TRANSMIT DATA TRANSMIT ESC

RECEIVE DATA RECEIVE ESC RECEIVE EXTERNAL REFERENCE CLOCK

MOD AND DEMOD FAULTS

BACKUP C/U DATA I/O

DATA SW ITCH MOTHERBOARD

Figure 4-11. Backup IDR Interface Switch

MN/SMS758 Rev. 3 4–33

Theory of Operation SMS-758 Modem Protection Switch

4.6.6 2:N IDR Interface Switch (1877 and 1879)

The 2:N IDR interface switch module switches all interface signals by relay. The prime interface switch module (Figure 4-12) has two 50-pin female D connectors.

• Terminal equipment interface J1 (top) is a DCE interface.

• Prime modem interface J2 (bottom) is a DTE interface.

The backup interface switch module (Figure 4-13) has one 50-pin female D connector.

The backup modem interface J1 is a DTE interface.

Note: This interface module can only be used in the SMS-758 or SMS-658A. Also, this interface can not be used in conjunction with the AS/895 or AS/896 IDR Interface Switch modules.

When the prime interface switch module (or the M:N switch itself) is powered down or in the default position, all signals are routed between the terminal equipment and the prime modem.

A buffered set of transmit data (SD) and reference clock (EXC) signals is switched to the “hot standby” backup modulator or demodulator, or to the offline prime modulator and demodulator when a backup operation occurs. The fault lines from the modem connector are routed through the interface switch modules to the M&C.

4.6.6.1 Specification

Circuits Supported SD, RD, EX C , T X D , T X C , T X O , RXD, RXC, RXO, BWO 1

through 4, BWI 1 through 4, A1I, A1O, A2I, A2O, DEMOD

FAULT, DMA. Switching Format All signals switched with dry contacts. Contact Arrangement Modulator signals: 16 poles.

Demodulator signals: 27 poles.

Ref. Clock: 2 poles.

4–34 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

4.6.6.2 Operation

When configuring modem setup on the front panel, it is recommended to select #9 - IDR 2:N for the interface selection.

Note: The 1877 and 1879 interface will not work when #5 - IDR is selected in the modem setup configuration. This interface cannot be used in conjunction with any interface switch modules that only support 1 backup. These include the AS/0895 and AS/0896 IDR modules. Check the rear of the switch and verify that none of the interface switch modules are the AS/0895 or AS/0896 modules.

4.6.6.3 Connector Pinouts

The 2:N IDR interface uses a 50-pin female D connector.

Screw locks provide mechanical security of the mating connector.

Signal Function Name Pin #

Ground - 1, 2 Send Data SD-A

SD-B

Receive Data RD-A

RD-B

Reference Clock EXC-A

EXC-B

8 KBPS TX Data TXD-A

TXD-B

8 KHz TX Clock Out TXC -A

TXC-B

1 KHz TX Octet In TXO-A

TXO-B

8 KBPS RX Data RXD-A

RXD-B

8 KHz RX Clock Out RXC-A

RXC-B

1 KHz RX Octet Out RXO-A

RXO-B

Backward Alarm 1 Out BWO1-C

BWO1-NC BWO1-NO

Backward Alarm 2 Out BWO2-C

BWO2-NC BWO2-NO

Backward Alarm 3 Out BWO3-C

BWO3-NC BWO3-NO

Backward Alarm 4 Out BWO4-C

BWO4-NC

BWO4-NO Backward Alarm 1 In BWI1 12 Backward Alarm 2 In BWI2 13

34 18 36 20 35 19 37 38 21 22 4 5 39 40 23 24 6 7 8 25 41 9 26 42 10 27 43 11 28 44

MN/SMS758 Rev. 3 4–35

Theory of Operation SMS-758 Modem Protection Switch

Backward Alarm 3 In BWI3 14 Backward Alarm 4 In BWI4 15 ADPCM 1 Audio In A1I-A

A1I-B ADPCM 1 Audio Out A1O-A

A1O-B ADPCM 2 Audio In A2I-A

A2I-B ADPCM 2 Audio Out A2O-A

A2O-B Demod Fault Relay DF-C

DF-NO Modulator Fault MF 49 Demodulator Fault DF 33 Deferred Maintenance Alarm DMA 17

45 29 46 30 47 31 48 32 16 50

Note: MF and DF inputs are only on the prime and backup modem interface connectors, not on the terrestrial data connector.

4–36 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

TRANSMIT DATA TRANSMIT ESC

RECEIVE DATA RECEIVE ESC RECEIVE EXTERNAL

REFERENCE CLOCK

TERRESTRIAL DATA I/O

THE RELAYS ARE SHOWN IN THE NON-ENERGIZED

NOTE:

POSITION CONNECTING THE TERRESTRIAL DATA AND PRIME MODEM CONNECTORS TOGETHER. STANDBY (S/B) SIGNALS ARE ROUTED TO THE OFFLINE BACKUP MODEM.

RX S/B

TX S/B

TRANSMIT DATA TRANSMIT ESC

RECEIVE DATA RECEIVE ESC RECEIVE EXTERNAL

REFERENCE CLOCK

FAULTS

DATA PATH SELECTION

TRANSMIT DATA

TRANSMIT ESC

RECEIVE DATA

RECEIVE ESC RECEIVE EXTERNAL

REFERENCE CLOCK

PRIME C/U DATA I/O

MOD AND DEMOD FAULTS

TX RELAYS

RX RELAYS

INSTRUCT ION DECODER

DATA SWITCH MOTHERBOARD

Figure 4-12. Prime 2:N IDR Interface Switch (1877)

MN/SMS758 Rev. 3 4–37

Theory of Operation SMS-758 Modem Protection Switch

DATA PATH SELECTION

TRANSMIT ESC

TRANSMIT DATA

RECEIVE DATA

RECEIVE ESC

RECEIVE EXTERNAL REFERENCE CLOCK

MOD AND DEMOD FAULTS

BACKUP DATA I/O

MOD RELAYS

DEMOD RELAYS

INSTRUCTION

DECODER

DATA SWITCH MOTHERBOARD

Figure 4-13. Backup 2:N IDR Interface Switch (1879)

4–38 MN/SMS758 Rev. 3

SMS-758 Modem Protection Switch Theory of Operation

4.6.7 2:N IBS/ASYNC Interface Switch (1694 and 1695)

The 2:N IBS/ASYNC interface switch module switches all interface signals by relay. The prime interface switch module (Figure 4-14) has two 50-pin female D connectors.

• Terminal equipment interface J1 (top) is a DCE interface.

• Prime modem interface J2 (bottom) is a DTE interface.

The backup interface switch module (Figure 4-15) has one 50-pin female D connector.

• The backup modem interface J1 is a DTE interface.

The prime interface switch module can plug into any of the interface switch module slots (A1 through A8) on the left side of the lower rear panel. The backup interface can plug into either A9 or A10.

Note: This interface module can only be used in the SMS-758 or SMS-658A. Also, this interface cannot be used in conjunction with the AS/0895 or AS/0896 1:N IDR Interface Switch modules.

When the prime interface switch module (or the M:N switch itself) is powered down or in the default position, all signals are routed between the terminal equipment and the prime modem.

A buffered set of transmit data (SD) or transmit clock (SCTE) and reference clock (EXC) signals is switched to the “hot standby” backup modulator or demodulator, or to the offline prime modulator and demodulator when a backup operation occurs.

The fault lines from the modem connector are routed through the interface switch modules to the M&C.

4.6.7.1 Specification

Circuits Supported SD, RD, EXC, SCTE, RXD, SCR, SCT , T X D PR IMARY FAULT,

SECONDARY FAULT, RTS, CTS, RLSD, RR, DSR. Switching Format All signals switched with dry contacts. Contact Arrangement Modulator signals: 12 poles.

Demodulator signals: 18 poles.

Ref. Clock: 2 poles.

MN/SMS758 Rev. 3 4–39

Theory of Operation SMS-758 Modem Protection Switch

4.6.7.2 Operation

When configuring the modem setup on the front panel, use the terrestrial type (G.703 15-pin D, V.35 34-pin, RS-422 37-pin D) for the interface selection. Refer to Figures 416 and 4-17 for diagrams, and Tables 4-7 and 4-8 for jumper tables describing how to set the jumpers for using each interface type.

Note: This interface cannot be used in conjunction with any Interface switch modules that only support 1 backup. These include the AS/0895 and AS/0896 IDR modules. Please check the rear of the switch and verify none of the interface switch modules are the AS/0895 or AS/0896 assembly.

4.6.7.3 Connector Pinouts

The 2:N IBS interface uses a 50-pin female D connector. Screw locks provide mechanical security of the mating connector.

Signal Function Name Pin #

Ground GND 1, 2 T1/E1 Send Data T1E1_SD-A

T1E1_SD-B

T1/E1 Receive Data T1E1_RD-A

T1E1_RD-B

External Clock IN EXC-A

EXC-B

RS422/V.35 Send Data SD-A

SD-B

RS422/V.35 Receive Data RD-A

RD-B ESC TX Data TXESCDAT 5 ESC RX Data RXESCDAT 7 RS422/V.35 Receive Timing SCR/RTA

SCR/RTB RS422/V.35 Transmit Timing SCT/STA

SCT/STB RS422/V.35 Terminal Timing SCTE/TTA

SCTE/TTB RS422 Transmit Octet R422TXOA

R422TXOB RS422 Receive Octet R422RXOA

R422RXOB RS422/V.35 Request to Send RTSA

RTSB V.35 Data Set Ready V.35_DSR 41 RS422/V.35 Clear To Send CTSA

CTSB RS422/V.35 Data Set Ready DSR/DMA

DSR/DMB RS422/V.35 Receiver Ready RR/RLSDA

RR/RLSDB

34 18 36 20 35 19 37 38 39 40

23 24 21 22 12 13 14 15 8 9 45 29

47 31 48 32 46 30

4–40 MN/SMS758 Rev. 3

Comtech EF Data SMS-758 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

About this Manual

Audience

Organization

Preface

Revision Numbering Scheme

Conventions Used in this Manual

Screen Output and Command Syntax

Notes

Cautions, Warnings, and Dangers

Heading Hierarchy

Case Sensitivity

References Used in this Manual

Military Standards

Trademarks

Related Documents

Reporting Comments or Suggestions Concerning this Manual

Returning a Product

Upgrading a Product

Product Training

Table of Contents

1.1 Scope

1.2 Purpose and Function

1.3 Description

1.4 Performance Specification

2.1 Unpacking

2.2 System Installation

2.2.1 Switch Setup

2.2.2 Modem Setup

2.3 System Requirements

2.4 External Connections

2.4.1 Data I/O

2.4.2 External RS485 and RS232 Interface (J1 and J2)

2.4.3 Modem Control RS485

2.4.4 On-Line Status (J4, J5)

2.4.5 Relay-Remote/Fault (J6)

2.4.6 Downlink Inputs (J7 through J10, J12 through J15)

2.4.7 Back-up Demods (J11, J16)

2.4.8 Prime Mod Inputs (J18 through J25)

2.4.9 Back-up Mod Inputs (J26, J36)

2.4.10 Offline IF Outputs (J17, J27)

2.4.11 IF Outputs (J28 through J35)

2.4.12 AC Power (J37, J38)

2.4.13 DC Power (J37, J38)

2.4.14 Ground (J37)

3.1 Front Panel Description

3.1.1 LED Indicators

3.1.2 Keypad and LCD Display

3.2 Switch Setup

3.2.1 System Setup

3.2.2 Modem Setup

3.2.3 Modem Configuration

3.2.4 Faults

3.2.5 Operational Modes

3.2.6 Status Menu

4.1 Monitor and Control

4.1.1 Theory of Operation

4.1.2 M&C Serial Interface

4.1.3 Remote Baud Rate

4.1.4 Remote Address

4.1.5 External Remote Serial Interface Selection

4.1.6 Battery

4.1.7 Error Response Function

4.1.8 External I/O Interrupt Arbitration

4.2 Modem Control Interface Specification

4.3 Relay-Remote Interface Specification

4.3.1 Command Structure

4.4 Fault Interface Specification

4.4.1 Controller fault

4.4.2 M:N Fault

4.4.3 Demodulator Signal Fault

4.5 Online Status Specification

4.5.1 Modulator Online Status

4.5.2 Demodulator Online Status

4.6 Interface Switches

4.6.1 RS-422/449 and MIL-STD-188-114/RS-449 Interface Switch

4.6.2 V.35 Interface Switch