Comtech EF Data DMD2401, DMD2401L User Manual

DMD2401/DMD2401L/

DMD2401 IBS/IDR

Satellite Modem

Installation and Operation Manual

TM065 - Rev. 3.3

May, 2002

- NOTICE -

2002, Radyne ComStream Corporation. This

manual may not in whole or in part be copied,
reproduced, translated or reduced to any
electronic or magnetic storage medium without
the written consent of a duly authorized officer of
Radyne ComStream Corporation.

Radyne ComStream Corporation  3138 E. Elwood St.  Phoenix, AZ 85034  [phone]  Fax: [phone]

Latest Software Revision Confirmation

When new features are added to Radyne ComStream Corporation equipment, the control
parameters are appended to the end of the Non-Volatile Section of the Remote
Communications Specification, and status of the features, if any, are added at the end of
the Volatile Section. If a remote M&C queries two pieces of Radyne ComStream
Corporation equipment with different revision software, they could respond with two
different sized packets. The remote M&C MUST make use of the non-volatile count value
to index to the start of the Volatile Section. If the remote M&C is not aware of the newly
added features to the product, it should disregard the parameters at the end of the Non­Volatile Section and index to the start of the Volatile Section.

Before creating any software based on the information contained in this document,
contact the Radyne ComStream Corporation Customer Service Department (602-437-9620)
to find out if the software revision for that piece of equipment is current and that no new
features have been added since the release of this document.

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Warranty Policy

Radyne ComStream Corporation Warranty Policy

Warranty and Service

Radyne ComStream Corporation (Seller) warrants the items manufactured and sold by Radyne ComStream
Corporation to be free of defects in material and workmanship for a period of two (2) years from date of

shipment Radyne ComStream Corporation’s obligation under its warranty is limited in accordance with the
periods of time and all other conditions stated in all provisions of this warranty.
This warranty applies only to defects in material and workmanship in products manufactured by Radyne
ComStream Corporation. Radyne ComStream Corporation makes no warranty whatsoever concerning
products or accessories not of its manufacture. Repair, or at Radyne ComStream Corporation’s option,
replacement of the Radyne ComStream Corporation products or defective parts therein shall be the sole
and exclusive remedy for all valid warranty claims.

Warranty Period

The applicable warranty period shall commence on the date of shipment from Radyne ComStream
Corporation’s facility to the original purchaser and extend for the stated period following the date of
shipment. Upon beginning of the applicable Radyne ComStream Corporation warranty period, all
customer’s remedies shall be governed by the terms stated or referenced in this warranty. In-warranty
repaired or replacement products or parts are warranted only for the remaining unexpired portion of the
original warranty period applicable to the repaired or replaced products or parts. Repair or replacement of
products or parts under warranty does not extend the original warranty period.

Warranty Coverage Limitations

The following are expressly not covered under warranty:

1. Any loss, damage and/or malfunction relating in any way to shipping, storage, accident, abuse,

2. Products, items, parts, accessories, subassemblies, or components which are expendable in

Warranty Replacement and Adjustment

Radyne ComStream Corporation will not make warranty adjustments for failures of products or parts which
occur after the specified maximum adjustment period. Unless otherwise agreed, failure shall be deemed to
have occurred no more than seven (7) working days before the first date on which a notice of failure is
received by Radyne ComStream Corporation. Under no circumstances shall any warranty exceed the
period stated above unless expressly agreed to in writing by Radyne ComStream Corporation.

Liability Limitations

This warranty is expressly in lieu of and excludes all other express and implied warranties,
Including but not limited to warranties of merchantability and of fitness for particular purpose, use,
or applications, and all other obligations or liabilities on the part of Radyne ComStream
Corporation, unless such other warranties, obligations, or liabilities are expressly agreed to in
writing by Radyne ComStream Corporation.

All obligations of Radyne ComStream Corporation under this warranty shall cease in the event its
products or parts thereof have been subjected to accident, abuse, alteration, misuse or neglect, or
which have not been operated and maintained in accordance with proper operating instructions.

alteration, misuse, neglect, failure to use products under normal operating conditions, failure to
use products according to any operating instructions provided by Radyne ComStream Corporation,
lack of routine care and maintenance as indicated in any operating maintenance instructions, or
failure to use or take any proper precautions under the circumstances.

normal use or are of limited life, such as but not limited to, bulbs, fuses, lamps, glassware, etc.
Radyne ComStream Corporation reserves the right to revise the foregoing list of what is covered
under this warranty.

TM065 - Rev. 3.3 iii

Warranty Policy DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem

In no event shall Radyne ComStream Corporation be liable for Incidental, consequential, special

or resulting loss or damage of any kind howsoever caused. Radyne ComStream Corporation’s
liability for damages shall not exceed the payment, if any, received by Radyne ComStream
Corporation for the unit or product or service furnished or to be furnished, as the case may be,
which is the subject of claim or dispute.

Statements made by any person, including representatives of Radyne ComStream Corporation,
which are inconsistent or in conflict with the terms of this warranty, shall not be binding upon
Radyne ComStream Corporation unless reduced to writing and approved by an officer of Radyne
ComStream Corporation.

Warranty Repair Return Procedure

Before a warranty repair can be accomplished, a Repair Authorization must be received. It is at this time
that Radyne ComStream Corporation will authorize the product or part to be returned to the Radyne
ComStream Corporation facility or if field repair will be accomplished. The Repair Authorization may be
requested in writing or by calling:

Radyne ComStream Corporation

3138 E. Elwood St.
Phoenix, Arizona 85034 (USA)
ATTN: Customer Support
Phone: [phone]
Fax: [phone]

Any product returned to Radyne ComStream Corporation for examination must be sent prepaid via the
means of transportation indicated as acceptable to Radyne ComStream Corporation. Return Authorization
Number must be clearly marked on the shipping label. Returned products or parts should be carefully
packaged in the original container, if possible, and unless otherwise indicated, shipped to the above
address.

Non-Warranty Repair

When a product is returned for any reason, Customer and its shipping agency shall be responsible for all
damage resulting from improper packing and handling, and for loss in transit, not withstanding any defect or
nonconformity in the product. By returning a product, the owner grants Radyne ComStream Corporation
permission to open and disassemble the product as required for evaluation. In all cases, Radyne
ComStream Corporation has sole responsibility for determining the cause and nature of failure, and Radyne

ComStream Corporation’s determination with regard thereto shall be final.

TM065 – Rev. 3.3 iv

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Record of Revisions

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem

Installation and Operation Manual

TM065 – Record of Revisions

Radyne ComStream Corporation is constantly improving its products and therefore the
information in this document is subject to change without prior notice. Radyne ComStream
Corporation makes no warranty of any kind with regard to this material, Including but not limited to
the implied warranties of merchantability and fitness for a particular purpose. No responsibility for
any errors or omissions that may pertain to the material herein is assumed. Radyne ComStream
Corporation makes no commitment to update nor to keep current the information contained in this
document. Radyne ComStream Corporation assumes no responsibility for use of any circuitry
other than the circuitry employed in Radyne ComStream Corporation systems and equipment.

Revision

Level

1.0 7-18-97 Preliminary Release

2.0 3-1-99 Added IBS/IDR Update information; New Interfaces Section; Updated

3.0 3-15-01 Revised manual format.

3.1 3-11-02 Revised Section 4, and 5.6.16. Added new product features.

3.2 5-28-02 Revised Technical Manual

3.3 5-29-02 Revised opcodes and commands.

Date Reason for Change

Remote Spec.

TM065 - Rev. 3.3 v

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem

This Page is Intentionally Left Blank

TM065 – Rev. 3.3 vi

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Table of Contents

Table of Contents

Section 1 – Introduction

1.0 Description _____________________________________________________ 1-1

1.1 DMD2401 Available Options________________________________________ 1-2

1.1.1 Reed-Solomon Codec ___________________________________________ 1-2

1.1.2 Sequential Decoding ____________________________________________ 1-2

1.1.3 Asynchronous Overhead Channel__________________________________ 1-2

1.1.4 Customized Options_____________________________________________ 1-3

1.1.5 8PSK Modulation _______________________________________________ 1-3

1.1.6 Analog AGC Voltage ____________________________________________ 1-3

1.1.7 Drop and Insert (D&I)____________________________________________ 1-3

1.1.8 Turbo Product Codec (TPC) ______________________________________ 1-3

Section 2 – Installation

2.0 Installation Requirements __________________________________________ 2-1

2.1 Unpacking ______________________________________________________ 2-1

2.2 Removal and Assembly____________________________________________ 2-1

2.3 Mounting Considerations___________________________________________ 2-2

2.4 Modulator Checkout ______________________________________________ 2-2

2.4.1 Initial Power-Up ________________________________________________ 2-2

Section 3 – Operation

3.0 Theory of Operation ______________________________________________ 3-1

3.1 DMD2401 Operation ______________________________________________ 3-1

3.2 Applications_____________________________________________________ 3-1

3.2.1 SCPC Point-to-Point Links________________________________________ 3-1

3.2.2 SCPC Point to Multi–Point Links in a Broadcast Application______________ 3-2

3.2.3 DAMA (Demand Assigned Multiple Access) __________________________ 3-2

3.2.4 TDMA (Time Division Multiple Access) Remote Site Application___________ 3-2

3.3 DMD2401 Initial Configuration Check_________________________________ 3-3

3.4 DMD2401 Automatic Uplink Power Control (AUPC Operation) _____________ 3-3

3.5 DMD2401 Asynchronous Overhead Operation__________________________ 3-4

3.5.1 Asynchronous Framing/Multiplexer Capability_________________________ 3-4

3.6 Standard IBS Mode_______________________________________________ 3-6

TM065 - Rev. 3.3 vii

Table of Contents DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem

3.7 Asynchronous Multiplexer Mode ____________________________________ 3-6

3.8 ESC Backward Alarms ____________________________________________ 3-6

3.8.1 To Disable the ESC Backward Alarms_______________________________ 3-7

3.9 IDR or IBS/D&I Configuration Instructions _____________________________ 3-7

3.9.1 IDR Configuration (Older Modems) _________________________________ 3-7

3.9.2 IBS/D&I Configuration (Older Modems)______________________________ 3-7

3.10 Configuring the DMD2401 for Drop and Insert _________________________ 3-7

3.10.1 Interface Type ________________________________________________ 3-8

3.10.2 Mode _______________________________________________________ 3-9

3.10.3 Data Rate____________________________________________________ 3-9

3.10.4 Terrestrial Framing - Drop Mode/Insert Mode _______________________ 3-10

3.10.4.1 Insert Terrestrial Frame Source ________________________________ 3-10

3.10.5 Alarms _____________________________________________________ 3-11

3.11 Drop and Insert Mapping_________________________________________ 3-12

3.12 Loopbacks____________________________________________________ 3-13

3.12.1 Terrestrial Loopback __________________________________________ 3-13

3.12.2 Baseband Loopback __________________________________________ 3-14

3.12.3 IF Loopback _________________________________________________ 3-14

Section 4 – User Interfaces

4.0 User Interfaces __________________________________________________ 4-1

4.1 Front Panel User Interface _________________________________________ 4-1

4.1.1 Front Panel LCD Display _________________________________________ 4-1

4.1.2 Front Panel LED Indicators _______________________________________ 4-2

4.1.3 Front Panel Keypad _____________________________________________ 4-2

4.1.4 Parameter Setup _______________________________________________ 4-3

4.2 Front Panel Control Screen Menus___________________________________ 4-4

4.2.1 Main Menus ___________________________________________________ 4-4

4.2.2 Modulator Menu Options and Parameters____________________________ 4-4

4.2.3 Demodulator Menu Options and Parameters__________________________ 4-6

4.2.4 Interface Menu Options and Parameters_____________________________ 4-9

4.2.5 Monitor Menu Options and Parameters_____________________________ 4-11

4.2.6 Alarms Menu Options and Parameters _____________________________ 4-12

4.2.7 System Menu Options and Parameters_____________________________ 4-20

4.2.8 Test Menu Options and Parameters _______________________________ 4-22

viii TM065 - Rev. 3.3

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Table of Contents

4.3 Terminal Mode Control ___________________________________________ 4-23

4.3.1 Modem Terminal Mode Control ___________________________________ 4-24

4.3.2 Modem Setup for Terminal Mode__________________________________ 4-24

4.4 Remote Port User Interface _______________________________________ 4-35

4.4.1 Protocol Structure _____________________________________________ 4-35

4.4.2 Protocol Wrapper______________________________________________ 4-35

4.4.3 Frame Description and Bus Handshaking ___________________________ 4-37

4.4.4 Global Response Operational Codes_______________________________ 4-38

4.4.5 Collision Avoidance ____________________________________________ 4-40

4.4.6 Software Compatibility __________________________________________ 4-42

4.4.7 Flow Control and Task Processing ________________________________ 4-42

4.4.8 RLLP Summary _______________________________________________ 4-43

4.4.9 DMD2401 Opcode Command Set _________________________________ 4-44

4.4.10 Modulator Command Set _______________________________________ 4-45

4.4.11 Demodulator Command Set_____________________________________ 4-46

4.4.12 Module Command Set _________________________________________ 4-47

4.4.13 Detailed Command Descriptions _________________________________ 4-47

4.4.13.1 DMD2401 Modulator_________________________________________ 4-47

4.4.13.2 DMD2401 Demodulator_______________________________________ 4-67

4.4.13.3 Module Queries & Commands _________________________________ 4-89

4.4.13.4 Default Values Modulator _____________________________________ 4-95

4.4.13.5 Default Values Demodulator___________________________________ 4-97

4.5 Terminal Port User Interface_______________________________________ 4-99

Section 5 – Electrical Interfaces

5.0 DMD2401 Connections____________________________________________ 5-1

5.1 AC Power Input/Switch ____________________________________________ 5-1

5.2 DC Power Input/Switch ____________________________________________ 5-1

5.3 DMD2401 with RS-422/-449 Data Interface ____________________________ 5-2

5.3.1 RCV IF IN (J1) _________________________________________________ 5-2

5.3.2 EXT REF IN (J2) _______________________________________________ 5-2

5.3.3 EXT CLK (J3)__________________________________________________ 5-2

5.3.4 XMIT IF OUT (J4)_______________________________________________ 5-2

5.3.5 TERMINAL (J5) ________________________________________________ 5-2

5.3.6 ALARM (J6) ___________________________________________________ 5-3

TM065 - Rev. 3.3 ix

Table of Contents DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem

5.3.7 REMOTE (J7)__________________________________________________ 5-4

5.2.9 DATA INTERFACE (J9)__________________________________________ 5-4

5.2.9.1 RS-232 Adapter to J9 __________________________________________ 5-5

5.2.9.2 V.35 Adapter to J9 ____________________________________________ 5-6

5.4 DMD2401 with RS-422/-449 Data Interface ____________________________ 5-7

5.4.1 RCV IF IN (J1) _________________________________________________ 5-7

5.4.2 EXT REF IN (J2) _______________________________________________ 5-7

5.4.3 EXT CLK (J3)__________________________________________________ 5-7

5.4.4 XMIT IF OUT (J4)_______________________________________________ 5-7

5.4.5 TERMINAL (J5) ________________________________________________ 5-7

5.4.6 ALARM (J6) ___________________________________________________ 5-8

5.4.7 REMOTE (J7)__________________________________________________ 5-8

5.4.8 ASYNC DATA (J17)_____________________________________________ 5-8

5.4.9 DATA INTERFACE (J9)__________________________________________ 5-8

5.5 DMD2401 IBS ___________________________________________________ 5-9

5.5.1 RCV IF IN (J1) _________________________________________________ 5-9

5.5.2 EXT REF IN (J2) _______________________________________________ 5-9

5.5.3 EXT CLK (J3)__________________________________________________ 5-9

5.5.4 XMIT IF OUT (J4)_______________________________________________ 5-9

5.5.5 TERMINAL (J5) ________________________________________________ 5-9

5.5.6 ALARM (J6) __________________________________________________ 5-10

5.5.7 REMOTE (J7)_________________________________________________ 5-10

5.5.8 SWITCH INTERFACE (J8) ______________________________________ 5-10

5.5.9 SYNC DATA (J10) _____________________________________________ 5-13

5.5.10 IBS ALARMS (J14)____________________________________________ 5-14

5.5.11 ASYNC (J15) ________________________________________________ 5-15

5.6 DMD2401 IDR with D&I___________________________________________ 5-16

5.6.1 RCV IF IN (J1) ________________________________________________ 5-16

5.6.2 EXT REF IN (J2) ______________________________________________ 5-16

5.6.3 EXT CLK (J3)_________________________________________________ 5-16

5.6.4 XMIT IF OUT (J4)______________________________________________ 5-16

5.6.5 TERMINAL (J5) _______________________________________________ 5-16

5.6.6 ALARM (J6) __________________________________________________ 5-17

5.6.7 REMOTE (J7)_________________________________________________ 5-17

5.6.8 SWITCH INTERFACE (J8) ______________________________________ 5-17

x TM065 - Rev. 3.3

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Table of Contents

5.6.9 SD (J9)______________________________________________________ 5-17

5.6.10 DDO (J10) __________________________________________________ 5-17

5.6.11 IDI (J11) ____________________________________________________ 5-17

5.6.12 RD (J12)____________________________________________________ 5-17

5.6.13 ESC ALARMS (J14)___________________________________________ 5-17

5.6.14 ESC 8K DATA (J15)___________________________________________ 5-19

5.6.15 G.703 BAL (J16) _____________________________________________ 5-20

5.6.16 ESC 64K Data/Voice/Async (J17) ________________________________ 5-20

5.7 DMD2401 IDR__________________________________________________ 5-23

5.7.1 RCV IF IN (J1) ________________________________________________ 5-23

5.7.2 EXT REF IN (J2) ______________________________________________ 5-23

5.7.3 EXT CLK (J3)_________________________________________________ 5-23

5.7.4 XMIT IF OUT (J4)______________________________________________ 5-23

5.7.5 TERMINAL (J5) _______________________________________________ 5-24

5.7.6 ALARM (J6) __________________________________________________ 5-24

5.7.7 REMOTE (J7)_________________________________________________ 5-25

5.7.8 SWITCH INTERFACE (J8) ______________________________________ 5-25

5.7.9 SD (J9)______________________________________________________ 5-25

5.7.10 G.703 BAL (J10) _____________________________________________ 5-25

5.7.11 RD (J12)____________________________________________________ 5-25

5.7.12 ESC ALARMS (J14)___________________________________________ 5-25

5.7.13 ESC 8K DATA (J15)___________________________________________ 5-25

5.7.14 ESC 64K DATA/AUDIO (J17) ___________________________________ 5-25

5.8 DMD2401 Universal Interface______________________________________ 5-26

5.8.1 RCV IF IN (J1) ________________________________________________ 5-26

5.8.2 EXT REF IN (J2) ______________________________________________ 5-26

5.8.3 EXT CLK (J3)_________________________________________________ 5-26

5.8.4 XMIT IF OUT (J4)______________________________________________ 5-26

5.8.5 TERMINAL (J5) _______________________________________________ 5-26

5.8.6 ALARM (J6) __________________________________________________ 5-27

5.8.7 REMOTE (J7)_________________________________________________ 5-27

5.8.8 SWITCH INTERFACE (J8) ______________________________________ 5-27

5.8.9 SD (J9)______________________________________________________ 5-29

5.8.10 DDO (J10) __________________________________________________ 5-29

5.8.11 IDI (J11) ____________________________________________________ 5-29

TM065 - Rev. 3.3 xi

Table of Contents DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem

5.8.12 RD (J12)____________________________________________________ 5-30

5.8.13 ESC ALARMS (J14)___________________________________________ 5-30

5.8.14 ESC 8K DATA (J15)___________________________________________ 5-31

5.8.15 G.703 BAL (J16) _____________________________________________ 5-32

5.8.16 ESC 64K Data/Voice/Async (J17) ________________________________ 5-32

5.9 Async Port Configuration Switches__________________________________ 5-34

5.9.1 AS/3771 Daughter Card_________________________________________ 5-35

5.9.2 AS/4803 Daughter Card_________________________________________ 5-36

Section 6 – Maintenance

6.0 Periodic Maintenance _____________________________________________ 6-1

6.1 Troubleshooting _________________________________________________ 6-1

6.2 DMD2401 Fault Philosophy_________________________________________ 6-1

6.2.1 Alarm Masks___________________________________________________ 6-2

6.2.2 Active Alarms __________________________________________________ 6-2

6.2.2.1 Major Alarms_________________________________________________ 6-2

6.2.2.2 Minor Alarms_________________________________________________ 6-2

6.2.2.3 Latched Alarms _______________________________________________ 6-2

6.3 DMD2401 Fault Tree Matrices ______________________________________ 6-2

6.3.1 Interpreting the Matrices _________________________________________ 6-4

6.4 DMD2401 Bit Error Rate (BER Curves) _______________________________ 6-4

6.5 DMD2401 AGC Curve_____________________________________________ 6-7

Section 7 – Technical Specifications

7.0 Introduction _____________________________________________________ 7-1

7.1 Transmit and Receive Data Rates ___________________________________ 7-1

7.2 Modulator Specifications___________________________________________ 7-1

7.3 Demodulator Specifications ________________________________________ 7-1

7.4 Front Panel LED Indicators_________________________________________ 7-2

7.5 Monitor and Control_______________________________________________ 7-3

7.6 Options ________________________________________________________ 7-3

7.7 Environmental ___________________________________________________ 7-3

7.8 Physical________________________________________________________ 7-3

xii TM065 - Rev. 3.3

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Table of Contents

Section 8 – Appendices

Appendix A – Reed-Solomon Codes _____________________________________ 8-1
Appendix B - Carrier Control __________________________________________ 8-11
B.0 States ________________________________________________________ 8-11
B.1 Description ____________________________________________________ 8-11

TM065 - Rev. 3.3 xiii

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Introduction

Section 1 – Introduction

1.0 Description

The Radyne Corporation DMD2401 and DMD2401L Satellite Modems (Figure 1-1) are
microprocessor-controlled Binary Phase Shift Keyed (BPSK), Quadrature Phase Shift Keyed
(QPSK), Offset Quadrature Phase Shift Keyed (OQPSK), or Trellis Coded 8 Phase Shift Keyed
(8PSK) Modulators/Demodulators. They are used as part of the transmitting and receiving ground
equipment in a satellite communications system. The modem is designed for service in an SCPC
system where two modems are set for continuous operation with each other.

Note: Unless specified, DMD2401 denotes both the DMD2401 and DMD2401L units.

This versatile equipment package combines unsurpassed performance with numerous user­friendly front panel programmable functions. The DMD2401 provides selectable functions for
Intelsat IBS/IDR, as well as closed networks. All of the configuration, monitor, and control
functions are available at the front panel. Operating parameters such as variable data rates, FEC
code rate, IF frequencies and IBS/IDR framing can be readily set and reconfigured from the front
panel by earth station operations personnel. Additionally, all functions can be accessed with a
terminal or personal computer via a serial link for complete remote monitor and control capability.
The DMD2401 operates at all standard IBS and IDR data rates up to 4.375 Mbps. Selection of
any data rate in closed network operation is provided over the range of 9.6 Kbps to 4.375 Mbps in
1 bps steps. The maximum symbol rate is 2.5 Msps, regardless of modulation type, FEC, code
rate or framing type.

The DMD2401 is designed to perform as both ends of a satellite Single Channel Per Carrier
(SCPC) link or as the VSAT remote site modem in a TDMA hub system in mesh or star topology
networks. The Modulator and Demodulator operate independently using BPSK, QPSK, OQPSK,
or 8PSK modulation in either SCPC or VSAT Modes.

The DMD2401 is also the ideal VSAT modem for use in a Point-to-Point Frame Relay Hybrid
Network. Other applications include FDMA, telephony, video conferencing, long-distance
learning, paging and newsgathering.

Refer to Table 1-1 for selection of any data rate that is provided over the following ranges:

Table 1-1. Data Rates

FEC 1/2 2/3 3/4 7/8

BPSK

QPSK

OQPSK

8PSK

The DMD2401 is programmable from the front panel. The program menu was specifically
designed for ease of use to quickly put the modem online and for any network changes. The
modem also can be monitored and controlled through the RS-485 or RS-232 serial control
channel.

TM065 - Rev. 3.3 1-1

4800 bps –

1250 Kbps

9600 bps –

2500 Kbps

9600 bps –

2500 Kbps

N/A Optional N/A N/A

N/A 7200 bps –

1875 Kbps

N/A 14400 bps –

3750 Kbps

N/A 14400 bps –

3750 Kbps

8400 bps –

2187.5 Kbps
16800 bps –

4375 Kbps

16800 bps –

4375 Kbps

Introduction DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem

The DMD2401 can track and acquire a carrier over a programmable range of ±1 kHz to ±42 kHz.
Acquisition times of less than 10 seconds are typical at data rates of 64 Kbps over a range of
± 25 kHz.

To facilitate link testing, the DMD2401 incorporates built-in ‘2047’ test pattern generators with
BER measurement capability. A user-selectable terrestrial and/or satellite loopback test capability
is also provided.

For applications requiring systems redundancy, multiple DMD2401 modems may be used with the
Radyne RCS11 1:1 Redundancy Switch or the RCS20 M:N (N < 9) Redundancy Switch. A full
range of industry-standard interfaces are available for the DMD2401, DMD2401L, and DMD2401
IBS/IDR. These include RS-232, V.35, RS-422/-449 and ITU G.703.

Available options for the DMD2401 includes a low data rate asynchronous serial overhead
channel for remote monitor and control. Additionally, a Sequential Codec is available for
applications requiring compatibility with existing systems.

Figure 1-1. DMD2401 Satellite Modem

1.1 DMD2401 Available Options

A wide range of options are available for the DMD2401 Satellite Modem. A brief description of
each follows:

1.1.1 Reed-Solomon Codec

The DMD2401 can be equipped with a Reed-Solomon outer codec with an interleaver as an
optional enhancement. The encoder and decoder are completely independent and meet IESS­308/-309 Specifications. Once prepped, this option can be installed in the field by following an
upgrade procedure.

Note: Custom Reed-Solomon codes are also available.

1.1.2 Sequential Decoding

The DMD2401 can also be equipped with an optionally installed sequential decoder. The
DMD2401 must be prepped for this option in the factory. Once prepped, the option can be added
by installing a daughter card on an existing header. Sequential Encoding/Decoding can operate
with 1/2, 3/4, and 7/8 Rates up to data rates of 4.375 Mbps.

1.1.3 Asynchronous Overhead Channel

The DMD2401 can be equipped with optional asynchronous overhead channel capability. The
option can be added in the field by installing a single interface PC board. The overhead channel
is proportional to the data rate (Baud Rate is approximately 1/2000 of the Data Rate for Standard
IBS and up to a maximum of 19.2 Kbaud for IBS Async).

1-2 TM065 – Rev. 3.3

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Introduction

1.1.4 Customized Options

The DMD2401 may be customized for specific customer requirements. Most
modifications/customization can be accomplished by means of firmware/software modifications.
The following are examples of the types of customization available to the user:

1. Customized Data Rates.

2. Customized Scrambler/Descramblers.

3. Customized Overhead Framing Structures.

4. Customized Modulation Formats.

5. Customized Uses for Asynchronous Overhead Channel.

1.1.5 8PSK Modulation

The DMD2401 can be equipped with 8PSK Modulation capability as an add-on option. The 8PSK
Option can be added by installing one IC into an existing socket.

1.1.6 Analog AGC Voltage

The DMD2401 can be equipped at the factory to produce an analog voltage equivalent to its AGC
for use in antenna controllers.

1.1.7 Drop and Insert (D&I)

The DMD2401 can be equipped at the factory with D&I as an add-on enhancement. The D&I
Functions are completely independent and can be programmed for n x 64 blocks of either T1 or
E1 Data Streams.

1.1.8 Turbo Product Codec (TPC)

The DMD2401 can be equipped at the factory with TPC as an add-on option. The TPC Option is
a daughter card, which can be added by installing the card on modems with the required header.

TPC works with all installed modulations on the DMD2401 and functions throughout the Modem’s
symbol rate limits. TPC is used to enhance performance of the DMD2401 Modem

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Introduction DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem

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1-4 TM065 – Rev. 3.3

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Installation

Section 2 – Installation

2.0 Installation Requirements

The DMD2401 can be installed within any standard 19-inch equipment cabinet or rack, and
requires 1 RU mounting space (1.75 inches) vertically and 21 inches of depth. Including cabling,
a minimum of 23-inches of rack depth is required. The rear panel is designed to have power
enter from the left and IF cabling enter from the right when viewed from the rear of the unit. Data
and control cabling can enter from either side although they are closer to the left. The unit can be
placed on a table or suitable surface if required.

There are no user-serviceable parts or configuration settings located inside the

DMD2401 chassis. There is a potential shock hazard internally at the power supply
module. DO NOT open the DMD2401 chassis under any circumstances.

Before initially applying power to the unit, it is a good idea to disconnect the transmit
output from the operating ground station equipment. This is especially true if the
current DMD2401 configuration settings are unknown, where incorrect settings could
disrupt existing communications traffic.

2.1 Unpacking

The DMD2401 Modulator was carefully packaged to avoid damage and should arrive complete
with the following items for proper installation:

1. DMD2401 Unit.

2. Power Cord, 6-foot with applicable AC connector.

3. Installation and Operation Manual.

2.2 Removal and Assembly

Carefully unpack the unit and ensure that all of the above items are in the carton. If the Prime AC
power available at the installation site requires a different power cord/AC connector, then
arrangements to receive the proper device will be necessary before proceeding with the
installation.

The DMD2401 Modulator is shipped fully assembled. It does not require removal of the covers for
any purpose in installation. The only replaceable assembly in the unit is the data interface and is
not intended to be accomplished in the field. Should the power cable AC connector be of the
wrong type for the installation, either the cable or the power connector end should be replaced.
The power supply itself is designed for universal application using from 100 to 240 VAC, 50 – 60

Hz, 1.0A.

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Installation DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem

2.3 Mounting Considerations

When mounted in an equipment rack, adequate ventilation must be provided. The ambient
temperature in the rack should be between 10° and 35° C, and held constant for best equipment
operation. The air available to the rack should be clean and relatively dry. The DMD2401 units

may be stacked one on top of the other up to a maximum of 10 consecutive units before providing
a 1 RU space for airflow.

Do not mount the DMD2401 in an unprotected outdoor location where there is direct contact with
rain, snow, wind or sun. The DMD2401 is designed for indoor applications only.
The only tools required for rack mounting the DMD2401 is a set of four rack mounting screws and
an appropriate screwdriver. Rack mount brackets are an integral part of the cast front bezel of the
unit and are not removable.

Shielded cables with the shield terminated to the conductive backshells are required in order to
meet EMC directives. Cables with insulation flammability ratings of 94 VO or better are required
in order to meet low voltage directives.

The following interface connections should be available at the mounting location as a minimum:

1. Prime AC Power.

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3. An RS-449 Data Interface Cable with a 37-Pin Male ‘D’ Sub-Connector.

2.4 Modulator Checkout

The following descriptions assume that the DMD2401 is installed in a suitable location with prime
AC power and supporting equipment available.

2.4.1 Initial Power-Up

Before initial powerup of the DMD2401, it is a good idea to disconnect the transmit output
from the operating ground station equipment. This is especially true if the current
modulator configuration settings are unknown, where incorrect settings could disrupt the
existing communications traffic. New units from the factory are normally shipped in a
default configuration which includes setting the transmit carrier off.

Turn the unit ‘ON’ by placing the rear panel switch (above the power entry connector) to the ‘ON’
position. Upon initial and subsequent power-ups, the DMD2401 microprocessor will test itself and
several of its components before beginning its main Monitor/Control program. These power-up
diagnostics show no results if successful. If a failure is detected, the Fault LED is illuminated.

The initial field checkout of the modem can be accomplished from the front panel or in the
Terminal Mode. The Terminal Mode has the advantage of providing full screen access to all of
the modem’s parameters, but requires a separate terminal or computer running a terminal
program. The unit is placed into terminal mode by setting two options via the front panel. The two
options are the Term Baud and Emulation settings found under the System M&C submenus.

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DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Installation

Terminal Setup:

Baud Rate: 19.2 K (Can be changed via front panel)
Data Bits: 8
Parity: No Parity (Fixed)
Stop Bits: 1 Stop Bit

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Installation DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem

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2-4 TM065 – Rev. 3.3

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Operation

Section 3 – Operation

3.0 Theory of Operation

A digital terrestrial interface supplies the modulator with a data stream. The data stream is
synchronized if the incoming stream is framed. The data is scrambled, and FEC is added. The
data is then convolutionally encoded, punctured, then constellation mapped. The resulting I&Q
symbols are digitally filtered. The data is then converted into an analog waveform and is vector
modulated onto an RF Carrier produced from the Transmit IF Synthesizer Circuitry.

3.1 DMD2401 Operation

A block diagram of the signal flow is shown in Figure 3-1 below. The modem is shown in a typical
application with customer data, Tx/Rx RF Equipment and an antenna.

Figure 3-1. Functional Block Diagram

3.2 Applications

Following are just a few representative forms of satellite communication links and networks in
which the DMD2401 modem may be used.

3.2.1 SCPC Point-to-Point Links

The most straightforward application for a satellite modem is to serve as the Data
Communications Equipment (DCE) for a point-to-point data link. When used in this mode, two
modems located at two different sites are tuned to complementary transmit and receive
frequencies. Each direction of the communications link may have the same or entirely different
transmission parameters. In this application, it is typical that the link is established and

maintained on a continuous basis, although a special “on demand” case is described later.

TM065 - Rev. 3.3 3-1

Operation DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem

3.2.2 SCPC Point to Multi–Point Links in a Broadcast Application

A broadcast application might involve the necessity of sending continuous or intermittent data

from one source and “broadcasting” the information to many remote locations. For instance,
constant pricing information and updates may be sent by a central location to many store
locations. There may be minor return information from the remotes acknowledging receipt.
Another broadcast application could be transmitting background music from a central location to
many store sites. In this case, there would be no return path.

The topology of the network in both of these broadcast examples would typically be called a “Star”
network. As shown in Figure 3-2, the shape of the configuration is drawn with the central “Hub” as
the center of the star and the remotes as points of the star. In both cases the transmit frequency
and other parameters are shared by the receiver of all the remotes.

Figure 3-2. Star Network Configuration

3.2.3 DAMA (Demand Assigned Multiple Access)

Suppose that a telephone network with a virtual switch between modems carrying digitized voice
information is to be simulated. We might use a central computer to assign a pair of frequencies
for any conversation and send this connection information to the proper sites to set up the
connection. In this application, a new network configuration is usable. That is a “Mesh” network
where any of the voice modems at any site can be programmed to link with any other modem.
The resulting link diagram looks like a mesh of interconnects.

Since the frequencies can be assigned on demand, the network is then called “Demand Assigned,
Multiple Access,” or DAMA.

3.2.4 TDMA (Time Division Multiple Access) Remote Site Application

In a TDMA network, the central Hub continually transmits a stream of outbound data containing
information for multiple remote sites, while the remote sites transmit back to the Hub on a timed
basis. Each of these remotes is said to “burst” its information back on a specific frequency. This
may be the same inbound frequency for all sites. Each of the remotes is responsible for
accessing its own information from the outbound data stream by reading the address assigned to
specific parts of the data. The TDMA network usually looks like the Star network shown in
Figure 3-2.

The DMD2401 is specifically designed to be usable as the remote site modem of a TDMA network
when coupled with a proper “Burst” demodulator at the hub site.

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DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Operation

3.3 DMD2401 Initial Configuration Check

The DMD2401 is shipped from the factory with preset factory defaults. Upon initial power-up, a
user check should be performed to verify the shipped modem configuration. Refer to Section 3,
Operation for the Modulator and Demodulator Front Panel Menu Screens to locate and verify the
following configuration settings are correct:

Note: Transmit (Tx) and Receive (Rx) Interface types are dependent upon the customer’s
order.

Standard DMD2401 Factory Configuration Settings
Modulator:

Data Rate: 2,048,000 Kbps
Forward Error Correction: 1/2 Rate Viterbi
Modulation: QPSK
Frequency: 70.000000 MHz

950.000000 MHz (L-Band Option)
Modulator Output Power: -30 dBm
Carrier: Off

Demodulator:

Data Rate: 2,048,000 Kbps
Forward Error Correction: 1/2 Rate Viterbi
Frequency: 70.000000 MHz

950.000000 MHz (L-Band Option)

To lock up the modem, turn the carrier ON, enter ‘IF Loopback Enable,’ or connect a loopback
cable from J1 to J4 on the rear panel of the modem.

3.4 DMD2401 Automatic Uplink Power Control (AUPC Operation)

The DMD2401 modem has an optional built-in provision for Automatic Uplink Power Control
(AUPC). AUPC attempts to maintain a constant Eb/No at the receive end of an SCPC link. This is
especially useful when operating over a satellite at Ku-Band frequencies in locations with high
rainfall periods.

Note: An Asynchronous or IBS Interface is required for AUPC. Also, IBS (Async Framing
Mode MUST be selected to provide a channel for AUPC operation.

The IBS (Async Framer Data Mode provides a service channel between the two sites of a link
permitting the modem processors to send messages and get responses over this channel. AUPC
can be set to operate on either or both directions of a link but always requires a bi-directional
channel. Therefore, both the Modulator and Demodulator interface mode must be set to IBS
(Async for the AUPC menus to be visible and for the AUPC function to operate properly. The
AUPC functions and their descriptions are shown below:

The AUPC menus are located under the Modulator Menu as shown in Section 4.

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Operation DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem

Function Description

AUPC ENABLE/DISABLE Enables/Disables the AUPC to function locally

AUPC Eb/No Desired Eb/N0 of remote modem

AUPC MIN LVL Sets minimum output power to be used

AUPC MAX LVL Sets maximum output power to be used

AUPC DEF LVL Sets default output power to be used

The basic AUPC operation is described as follows: Assume that the two modems, one at each
end of the link, are set to AUPC operation. Only one direction is discussed, but the same

functions could be occurring in both directions simultaneously. Modem “A” is transmitting to
modem “B” under normal conditions and modem “B” has a receive Eb/No of 7.5 dB. Modem “A”
has been set to an AUPC Eb/No on the front panel of 7.5 dB, and is currently outputting –15 dBm.
Next, it begins raining at location “B”, and the Eb/No drops to –7.0 then –6.8 dB. Modem “B” is
constantly sending update messages to “A” and reports the current Eb/No. When “A” sees the
drop in Eb/No, it slowly begins to raise the output power, and raises it again when it sees further
drops. As the rain increases in intensity, and the Eb/No decreases again, “A” continues to
increase its power level to compensate, and when the rain diminishes and quits, it lowers its
power level to compensate. The operation is therefore a feedback control loop with the added
complication of a significant time delay.

There are safeguards built into the AUPC system. First, the Modulator has two additional
parameters, which allow control of the maximum and minimum power output levels. Second, a
default power level is specified which takes precedence over the output power level during signal
loss or loss of AUPC channel communication. The default power level should normally be set to a
high enough level to reestablish communication regardless of rain fade. The other controls are
built into the operating control software to limit response times and detect adverse operating
conditions.

3.5 DMD2401 Asynchronous Overhead Operation

3.5.1 Asynchronous Framing/Multiplexer Capability

The Asynchronous Framing/Multiplexer is capable of multiplexing a relatively low-speed overhead
channel onto the terrestrial data stream resulting in a slightly higher combined or aggregate data
rate through the modem. The overhead channel is recovered at the far end. This added channel
is termed variously “An Overhead Channel”, ”Service Channel”, “Async Channel” or in IESS
terminology an “ES to ES Data Channel.” The basic frame structure used by the multiplexer is
specified in the IESS-309 standard, Page 60, Figure 10, resulting in a 16/15 aggregate to through
data ratio.

For Regular Async. (Standard IBS), the Baud Rate is approximately 1/2000 of the Data Rate
listed in the table below. For Enhanced Async. (IBS Async.), the Baud Rate is selectable, but
limited by the Data Rate. The maximum Baud Rate is 19,200 bps for IBS Async.

Two software-controlled modes are designed into the card to best utilize the available bits;
“Standard IBS” and “IBS (Async)”. The characteristics of the Channel Interface is also determined
by the standard or Async mode.

The Async Channel can be set under software-control to either RS-232 or RS-485 mode. The pin
assignments for both modes are shown in Table 1. The “RS-485” setting controls the output into
tri-state when the modem is not transmitting data, allowing multiple modem outputs to be
connected together.

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DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Operation

Kbps

Baud Rate

Example for

Standard

IBS

Kbps

Baud Rate

Example for

Enhanced

Mode

128 64 9.6 300
256 128 19.2 600
384 192 32 600
512 256 64 1200
640 320 128 2400
768 384 192 4800

896 448 256 4800
1024 512 320 9600
1152 576 384 9600
1280 640 448 9600
1408 704 512 9600
1536 768 576 9600
1664 832 640 19200
1792 896 704 19200
1920 960 768 19200
2048 1024 832 19200

896 19200

960 19200
1024 19200
1088 19200
1152 19200
1216 19200
1280 19200
1344 19200
1408 19200
1472 19200
1536 19200
1600 19200
1664 19200
1728 19200
1792 19200
1856 19200
1920 19200

1984 19200

2048 19200

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Operation DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem

3.6 Standard IBS Mode

In the first or “Normal” mode, all bit assignments are per the IBS standard. The bits of Overhead
Housekeeping byte 32 are implemented as shown below:

Bit 1

ES to ES Data
Channel

This bit is routed directly to the ES to ES Data
Channel. Its data rate is 1/512th of the aggregate rate
(0r 1/480th of the through terrestrial data rate, and is
normally used to super-sample an asynchronous data
channel.

Bit 2
Bit 3

Bit 4
Bits 5 and 6
Bits 7 and 8

The ratio of the through terrestrial data channel rate to the aggregate rate is 15/16.
The standard transmit and receive channels of the ES to ES data channel in standard IBS mode
are raw channels operating at the specific bit rate as controlled by the data channel rate, without
buffering. In addition, no clocks are provided with this channel. Since it would be rare that the
data rate provided was exactly that required for a standard rate device, the only method of
communicating using this channel is to allow it to super-sample the user data.

Frame Alignment Part of the Frame Alignment word.
Backward Alarm Transmit and Receive with main processor to activate

main alarm/LED
Multiframe Message As per IBS
Spare Not currently utilized
Encryption Utilization Not currently utilized

3.7 Asynchronous Multiplexer Mode

Since many of the frame bits in the standard IBS mode are not used, an “Enhanced” multiplexer
mode has been implemented that can be engaged under software control. Since this mode
changes the use of many of the framed non-data bits, this mode is only usable when the
DMD2401 is at both ends of a link. In this mode, the overhead signaling bytes 16 and 48 can be
used to implement a significantly higher speed ES to ES Data Channel under software control.
When implemented, this rate is 16 times that of the normal IBS standard, or 1/30th of the
terrestrial data rate (1/32nd of the aggregate rate).

Note: The IBS Async mode MUST be selected for true Asynchronous channel operation to
be available.

3.8 ESC Backward Alarms

When running in IDR Mode and if the modem has the ESC Option, there will be four Backward
Alarms available for use by the earth stations at each end of the link (both ends must have the
ESC option). These alarms are accessed via the ESC ALARMS Port. The four alarms are
controlled by four relays, each having a normally open, normally closed, and a common
connection. The common connections of these relays (referred to as Backward Alarm Inputs) can
be connected to whichever system on the earth station that the user wishes to trigger the
backward alarm. When ground is applied to the common (input) connection of one of these
relays, that relay and associated backward alarm will then be in a “no fault” state. When the
ground is removed, the relay and the associated Tx Backward Alarm will toggle to the faulted
state. When in the faulted state, the receive end of the link will receive that backward alarm that
is initiated at the transmit end of the link.

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DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Operation

The user can connect whichever systems on the earth stations that they desire to these Backward

Alarms Relays as long as they will supply ground to the Backward Alarm Relay Input in the “no
fault” condition and the ground will be removed in the “faulted” condition.

For example: the user could connect the Demod Summary Fault of the modem to the Backward
Alarm 1 Input, so that if the demod went into Major Alarm (such as a Carrier Loss), Backward
Alarm 1 would be transmitted to the receive end of the link. At the receive end, it would show up
as Rx Backward 1 (Receive Backward Alarm 1).

3.8.1 To Disable the ESC Backward Alarms

If the ESC ALARMS Port will not be used and the Backward Alarm Indications are to be disabled,
connect the following pins of the ESC ALARMS Port:

Connect Pins 1, 10, 11, 22 and 23 (connect all together). Pin 1 is ground and Pins 10, 11, 22, and
23 are the inputs of Backward Alarms 1 through 4. By connecting these four pins to ground
(Pin 1) the Backward Alarms will be disabled and indicate “PASS” for BK1 through BK4.

3.9 IDR or IBS/D&I Configuration Instructions

Note: Newer Modems are Front Panel Configurable (disregard Sections 3.9.1 and 3.9.2).
To check; from the Front Panel (Section 4.2.7), go to System Menu, Firmware Rev. Menu,

‘DaughterCPLD’, and check for F04230 Revision C or above, or F04821.

3.9.1 IDR Configuration (Older Modems)

1. In this configuration, J17 on the back panel will be used as the ESC Port.

2. Attach the 10 Pin Ribbon Cable from J17 on the Back Panel to J3 on the AS/3760
Interface Card.

3. Remove Jumpers R38 and R40 located on the AS/3771 Daughter Card.

4. Cycle power on the unit.

3.9.2 IBS/D&I Configuration (Older Modems)

1. In this configuration, J17 on the back panel will be used as the ES-ES Communications
Port.

2. Attach the 10 Pin Ribbon Cable from J17 on the Back Panel to J11 on the AS/3771
Daughter Card.

3. Install Jumpers R38 and R40 located on the AS/3771 Daughter Card.

4. Cycle power on the unit.

3.10 Configuring the DMD2401 for Drop and Insert

Several dependencies exist when configuring the modem for Drop and Insert (D&I). The following
paragraphs explain these dependencies and provide the user with the information required to
ensure smooth transition into Drop & Insert and to minimize the potential impact of these
dependencies.

TM065 - Rev. 3.3 3-7