Radyne, Inc. • 3138 E. Elwood St. • Phoenix, AZ 85034 •(602) 437-9620 • Fax: (602) 437-4811
Latest Software Revision Confirmation
When new features are added to Radyne, Inc. 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, Inc. 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 Non -Volatile 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, Inc. Customer Serv ice Department at (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.
Radyne, Inc. (Seller) warrants the items manufactured and sold by Radyne, Inc. to be free of defects in
material and workmanship for a period of two (2) years from date of shipment Radyne, Inc.’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,
Inc. Radyne, Inc. makes no warranty whatsoever concerning products or accessories not of its
manufacture. Repair, or at Radyne, Inc.’s option, replacement of the Radyne, Inc. 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, Inc.’s facility to the
original purchaser and extend for the stated period following the date of shipment. Upon beginning of the
applicable Radyne, Inc. 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:
5 Any loss, damage and/or malfunction relating in any way to shipping, storage, accident, abuse,
alteration, misuse, neglect, failure to use products under normal operating conditions, failure to
use products according to any operating instructions provided by Radyne, Inc., lack of routine care
and maintenance as indicated in any operating maintenance instructions, or failure to use or take
Warranty Replacement and Adjustment
Radyne, Inc. 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, Inc. Under no circumstances shall any warranty exceed the period stated above unless expressly
agreed to in writing by Radyne, Inc.
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 Inc., unless such other
warranties, obligations, or liabilities are expressly agreed to in writing by Radyne, Inc.
All obligations of Radyne, Inc. 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.
In no event shall Radyne, Inc. be liable for Incidental, consequential, special or resulting loss or
damage of any kind howsoever caused.
any proper precautions under the circumstances.
5 Products, items, parts, accessories, subassemblies, or components which are expendable in
normal use or are of limited life, such as but not limited to, bulbs, fuses, lamps, glassware, etc.
Radyne, Inc. reserves the right to revise the foregoing list of what is covered under this warranty.
Radyne, Inc.’s liability for damages shall not exceed the payment, if any, received by Radyne, Inc.
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, Inc., which are inconsistent
or in conflict with the terms of this warranty, shall not be binding upon Radyne, Inc. unless
reduced to writing and approved by an officer of Radyne, Inc.
Warranty Repair Return Procedure
Before a warranty repair can be accomplished, a Repair Authorization must be received. It is at this time
that Radyne, Inc. will authorize the product or part to be returned to the Radyne, Inc. facility or if field repair
will be accomplished. The Repair Authorization may be requested in writing or by calling:
Radyne, Inc.
3138 E. Elwood St.
Phoenix, Arizona 85034 (USA)
ATTN: Customer Support
Phone: (602) 437-9620
Fax: (602) 437-4811
Any product returned to Radyne, Inc. for examination must be sent prepaid via the means of transportation
indicated as acceptable to Radyne, Inc. 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, Inc. permission to open
and disassemble the product as required for evaluation. In all cases, Radyne, Inc. has sole responsibility
for determining the cause and nature of failure, and Radyne, Inc.’s determination with regard thereto shall
be final.
TM051 – Rev. 5.8 iv
DMD15/DMD15L IBS/IDR Satellite Modem Record of Revisions
DMD15/DMD15L IBS/ IDR Universal Satellite
Installation and Operation Manual
TM051 – Record of Revisions
Radyne, Inc. is constantly improving its products and therefore the information in this document is
subject to change without prior notice. Radyne, Inc. 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, Inc. makes no commitment to update nor to keep current the
information contained in this document. Radyne, Inc. assumes no responsibility for use of any
circuitry other than the circuitry employed in Radyne, Inc. systems and equipment.
Revision
Level
1.0 6-18-96 Initial Release.
2.0 9-1-96 Expanded Drop and Insert Section, updated menu trees and descriptions,
Loopback Figures, expanded Principles of Operation Section, added IBS
Conditions and Faults Table, added new Universal Interface Illustrations and
pinout tables.
additional Interface Pinout Tables and descriptions.
Definitions, minor rearrangements and clarifications.
corrections to pinout tables.
minor corrections
TM051 - Rev. 5.8 v
DMD15/DMD15L IBS/IDR Satellite Modem
TM051 – Rev. 5.8 vi
DMD15/DMD15L IBS/IDR Satellite Modem Table of Contents
3.5 Earth Station to Earth St at ion (ES-ES) Communications Port ______________ 3-5
(Async Port J9)______________________________________________________ 3-5
The Radyn, Inc. DMD15/DMD15L Satellite Modem (Figure 1-1) offers the best features of a
sophisticated programmable IBS/IDR and Closed Network Modem, at an affordable price.
This versatile equipment package combines unsurpassed performance with numerous userfriendly Front Panel Programmable Functions. The DMD15/DMD15L provides selectable
functions for different services: Intelsat IDR and IBS, as well as closed networks. All of the
configuration and Monitor and Control (M&C) Functions are available at the Front Panel.
Operating parameters, such as variable data rates, FEC Code Rate, modulation type, IF
frequencies, IBS/IDR Framing and interface type can be readily set and changed at 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 monitoring and control
capability.
The DMD15/DMD15L operates at all standard IBS and IDR Data Rates up to 8.448 Mbps.
Selection of any data rate is provided over the range of 9.6 Kbps to 10 Mbps in 1 bps steps.
For applications requiring system redundancy, the DMD15/DMD15L Modem may be used with the
Radyne , Inc. RCS11 1:1 Redundancy Switch or the RCS20 M:N (N < 9) Redundancy Switch. An
optional Internal Engineering Service Channel Unit is available to provide voice, data, and alarms
for Intelsat IDR applications.
A full range of Industry Standard Interfaces is available for the DMD15/DMD15L. Interface types
are selectable from V.35, RS-232, RS-422/449 and ITU G.703.
Figure 1-1. DMD15/DMD15L Universal Satellite Modem Front Panel
1.1 DMD15/DMD15L Available Options
A wide range of options is available for the DMD15/DMD15L Satellite Modem.
1.1.1 Internal High Stability
The DMD15/DMD15L can be equipped with a 1x10
an add-on enhancement.
-7
or better Stability Frequency Reference as
1.1.2 Reed-Solomon Codec
The DMD15/DMD15L can be equipped with a Reed-Solomon (R-S) Outer Codec with an
interleaver as an optional add-on enhancement. The encoder and decoder are completely
independent and meet the IESS-308/309/310 specification. Once prepped, this option can be
installed in the field by installing five ICs into existing sockets. The DMD15/DMD15L must be
prepped for this option.
Note: Custom Reed-Solomon codes are also available.
TM051 - Rev. 5.8 1-1
Introduction DMD15/DMD15L IBS/IDR Satellite Modem
1.1.3 Turbo Codec
The DMD15/DMD15L can be equipped with an optional Turbo Codec Outer Code. This option
must be installed at the factory.
1.1.4 Drop and Insert (D&I)
The DMD15/DMD15L can be equipped with a D&I Interface as an add-on enhancement. This
option can be added in the field by installing one IC into an existing socket. The D&I Functions
are completely independent and can be programmed for n x 64 blocks for either a T1 or E1 Data
Stream.
1.1.5 8PSK Modulation
The DMD15/DMD15L can be equipped with 8PSK Modulation/Demodulation capability as an addon option. The 8PSK Option can be added by installing 2 ICs into existing sockets.
1.1.6 OQPSK Modulation
The DMD15/DMD15L can be equipped with an OQPSK modulation/demodulation capability as an
add-on option. The option can be added in the field by installing one IC into an existing socket.
1.1.7 16QAM Modulation
The DMD15/DMD15L can be equipped with a 16QAM Modulation/Demodulation capability as an
add-on option. The 16QAM option can be added by installing 2 ICs into existing sockets.
1.1.8 Sequential Decoding
The DMD15/DMD15L can be equipped with a sequential decoding option that can be installed as
an add-on option. The DMD15/DMD15L must be prepped for this option in the factory. Once
prepped, the option can be added by installing 3 ICs into existing sockets. Sequential
Encoding/Decoding can operate with 1/2, 3/4, and 7/8 Rates, up to data rates of 2.048 Mbps.
1.1.9 Earth Station-to-Earth Station (ES-ES) Communications
The DMD15/DMD15L can be equipped with an asynchronous overhead channel capability as an
add-on option. The option can be added in the field by installing 2 ICs into existing sockets. The
overhead channel is proportional to the data rate (2,400 baud per 64 KB) up to a maximum of
19.2 Kbaud.
1.1.10 Analog AGC Voltage
The DMD15/DMD15L can be equipped at the factory to produce an analog voltage equivalent to
its AGC for use in antenna controllers.
1.1.11 Internal Engineering Service Channel (ESC)
The DMD15/DMD15L can be equipped with an internal ESC. This unit is a card on the Universal
Interface Module (UIM). The DMD15/DMD15L can be updated with an ESC capable UIM in the
field with no other changes required.
1.1.12 OM73 Compatible
1-2 TM051 – Rev. 5.8
DMD15/DMD15L IBS/IDR Satellite Modem Introduction
The DMD15/DMD15L can be equipped with an optional OM73 scrambler at the customer’s
request. This option must be prepped at the factory. Once installed, selection of the OM73
Scrambler/Descrambler will automatically invert the baseband data on the Modulator/Demodulator
respectively. This configuration is required to run compatible with the OM73 Modem.
1.1.13 Back Panel Options
The DMD15/DMD15L has several optional Interface Modules available (refer to Figures 5-1
through 5-5). These include:
These Interface Modules are available with AC or DC Power Input Modules and the following
Transmit and Receive schemes.
IF Transmit and Receive
L-Band Transmit and Receive
IF Transmit, L-Band Receive
IF Receive Only
L-Band Receive Only
1.1.14 Customized Options
The DMD15/DMD15L may be customized for specific customer requirements. Most modifications
or customization can be accomplished by means of firmware/software modifications.
The following are examples of the types of customization available to the user:
Customized Data Rates.
Customized Scrambler/Descramblers.
Customized Overhead Framing Structures.
Customized Modulation Formats.
Customized Uses for the Earth Station-to-Earth Station (ES-ES) Overhead Channel.
Contact the Radyne , Inc. Customer Service or Sales Department at (602) 437-9620 for all
requests.
TM051 - Rev. 5.8 1-3
DMD15/DMD15L IBS/IDR Satellite Modem Installation
Section 2 – Installation
2.0 Installation Requirements
The DMD15/DMD15L Modem is designed to be installed within any standard 19-inch wide
equipment cabinet or rack, and requires one rack unit (RU) of 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 of the DMD15/DMD15L is designed to have power enter from the right
and IF Cabling enter from the left when viewed from the rear of the modem. Data and control
cabling can enter from either side although they are closer to the right. The unit can be placed on
a table or suitable surface if required.
There are no user-serviceable parts o r configu ration set tings lo cated insid e
the DMD15/DMD15L Chassis. There is a potential shock hazard internally at
the power supply module. DO NOT open the DMD15/DMD15L 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 DMD15/DMD15L configuration settings are
unknown, where inco rrect settings could disrupt existing communications
traffic.
2.1 Unpacking
The DMD15/DMD15L Modem was carefully packaged to avoid damage and should arrive
complete with the following items for proper installation:
1. DMD15/DMD15L Modem 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 DMD15/DMD15L Modem Unit is shipped fully assembled and does not require removal of the
covers for any purpose in installation. The only replaceable assembly in the unit is the Universal
Interface Module (UIM).
TM051 - Rev. 5.8 2-1
Installation DMD15/DMD15L IBS/IDR Satellite Modem
Always ensure that power is removed from the DMD15/DMD15L before
removing or installing a UIM. Failure to do so may cause damage to the
equipment.
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 to 60 Hz, 1.0 A.
2.3 Mounting Considerations
When mounted in an equipment rack, adequate ventilation must be provided. The ambient
temperature in the rack should preferably 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
modem units may be stacked one on top of the other to a maximum of 10 consecutive units
before providing one RU of space for airflow. Modem units should not be placed immediately
above a high heat or EMF Generator to ensure the output signal integrity and proper receive
operation.
Do not mount the DMD15/DMD15L in an unprotected outdoor location where there is direct
contact with rain, snow, wind or sun. The modem is designed for indoor applications only. The
only tools required for rack mounting the DMD15/DMD15L is a set of four rack-mounting screws
and the appropriate screwdriver. Rack mounting brackets are an integral part of the cast front
bezel of the unit and are not removable.
2.4 DMD15/DMD15L Initial Configuration Check
The DMD15/DMD15L is shipped from the factory with preset factory defaults. Upon initial powerup, a user check should be performed to verify the shipped modem configuration. Refer to
Section 4, User Interfaces to locate and verify that the following configuration settings are correct:
The DMD15/DMD15L Interface Type (V.35, RS-422, RS-232, G.703, etc.)
MUST be selected from the F ront Pane l BEFORE th e mating co nnecto rs are
installed. Failure to do so may cause damage to the Universal Interface
Module. Power up the DMD15/DMD15L, select the appropriate interface
type, and then install the mating connectors.
Note: Transmit (Tx) and Receive (Rx) Interface types are dependent upon the customer’s
order.
2-2 TM051 – Rev. 5.8
DMD15/DMD15L IBS/IDR Satellite Modem Installation
Standard DMD15/DMD15L Factory Configuration Settings
Note: The above modem configuration can be set by implementing Strap Code 26.
Refer to Table 3-1 for an explanation and tabular listing of available Strap Codes.
To lock up the modem, enter ‘IF Loopback Enable’ under the Test menu, or connect a Loopback
Cable from J1 to J2 on the rear panel of the modem.
2.5 Modulator Checkout
The following descriptions assume that the DMD15/DMD15L is installed in a suitable location with
prime AC power and supporting equipment available.
2.5.1 Initial Power-Up
Before initial power up of the DMD15/DMD15L, 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, w here incorrect settings could disrupt the existing
communications traffic. New un its f rom t he f acto ry are normally sh ipped in
a default configuration which includes setting the transmit carrier off.
Turn on the unit by placing the Rear Panel Switch (located above the power entry connector) to
the ‘ON’ position. Upon initial and subsequent power-ups, the DMD15/DMD15L 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
will illuminate.
TM051 - Rev. 5.8 2-3
Installation DMD15/DMD15L IBS/IDR Satellite Modem
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.
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
2-4 TM051 – Rev. 5.8
DMD15/DMD15L IBS/IDR Satellite Modem Operation
Section 3 – Operation
3.0 Theory of Operation
The DMD15/DMD15L is designed in three major sections: Universal Interface, Baseband
Processing, and Universal Modem.
3.1 DMD15/DMD15L Functional Block Diagram
Figures 3-1a through 3-1c represent the DMD15/DMD15L Functional Blocks. The modem is
shown in a typical application with customer data, Tx/Rx RF equipment and an antenna.
The Universal Interface Module (UIM) is a field-replaceable module that plugs into the rear of the
DMD15/DMD15L. The UIM provides the interconnection points (J3 - J8) for Terrestrial Data and
Clock to the Modem. The UIM also contains a Connection Port for an Asynchronous Data
Channel (J9) for use in Earth Station-to-Earth Station (ES-ES) communications. Additionally, the
UIM provides connection points (J11) for Form-C modem Status Relays. An illustration of two
versions of the UIM is shown in Figure 3-2, and Functional Block Diagrams are shown in
Figure 3-3.
Synchronous Tx Data and Clock enters the UIM and is routed to either the RS-422, RS-232, or
V.35 Receiver as the selected M&C Processor. The signals are then converted to an RS-422
balanced format and sent to the Baseband (BB) Processor Card. Receive Data from the BB
Processor Card undergoes the reverse process where it is converted from RS-422 Balanced
format and routed to the RS-422 or V.35 Drivers.
3.4 G.703 Interface
Either Balanced or Unbalanced G.703 Data is routed from the ‘Send Data In’ Connections to the
G.703 Receiver. The G.703 Receiver recovers a clock from the data stream, converts the clock
and data to an RS-422 balanced format, and routes the clock and data to the BB Processor. The
reverse process is performed on the Receive Data Stream where the G.703 Data exits the
modem at the ‘Receive Data Out’ Connection. The G.703 Interface is designed to operate at the
following data rates:
Additionally, the line code is selected when the interface type is selected with the exception that
T1 may use B8ZS or AMI as selected at the Front Panel.
The G.703 Interface also contains two additional ports that can operate at T1 or E1 that provides
a four port D&I Interface. The ‘Drop Data Out’ Port provides an unaltered Send Data Output that
can be used for daisy chaining additional systems. On the receive side, a T1 or E1 Data Stream
3-4 TM051 – Rev. 5.8
DMD15/DMD15L IBS/IDR Satellite Modem Operation
can be connected to the ‘Insert Data In’ Port where received data will overwrite ‘dropped on’ the
T1/E1 Data Stream. The modified T1/E1 Data Stream will then exit the modem out of the
‘Receive Data Out’ Port.
3.5 Earth Station to Earth Station (ES-ES) Communications Port
(Async Port J9)
The UIM contains a selectable RS-232, or RS-485 Asynchronous Communications Port for EarthStation-to-Earth-Station Communications. The data is routed from the 9-Pin “D” Connector J9 to
one of the M&C Processor UARTS on the Baseband Processor Card. The baud rate and protocol
can be selected from the Front Panel.
3.6 Terrestrial Loopback
The UIM also provides for terrestrial loopback. For Tx Terr Loopback, Tx Data, after passing
through the Line Interface is looped back to the Rx Data line drivers. For RX Terr Loopback, the
Receive Data from the satellite is looped back for retransmission to the satellite providing a far
end loopback. Tx/Rx Loopback provides both loopbacks simultaneously. Refer to Figures 3-4
through 3-6 for loopback functional block diagrams.
3.7 Modem Status
The UIM provides several status indications, which are controlled by the M&C Processor.
Form-C Contacts:
The UIM provides three Form-C Relays under processor control that appear at J11.
Mod Fault: De-energized when any transmit side fault is detected.
Demod Fault: De-energized when any receive side fault is detected.
Common Fault: De-energized when any fault that is not explicitly a Tx or
Rx Fault such as an M&C or Power Supply Fault.
Open Collector Faults:
The UIM provides two Open Collector Faults that appear at Pins 28 & 10 on J8.
Mod Fault: Will sink up to 20 ma (maximum) until a transmit or
common fault is detected. Will not sink current if a fault
is detected.
Demod Fault:Will sink up to 20 ma (maximum) until a receive or
common fault is detected. Will not sink current if a fault
is detected.
The open collector faults are intended for use in redundancy switch applications in order to
provide quick status indications.
TM051 - Rev. 5.8 3-5
Operation DMD15/DMD15L IBS/IDR Satellite Modem
Figure 3-4. Loopback Functional Block Diagram
3-6 TM051 – Rev. 5.8
DMD15/DMD15L IBS/IDR Satellite Modem Operation
Figure 3-5. Loopback Functional Block Diagram
Figure 3-6. Loopback Functional Block Diagram
TM051 - Rev. 5.8 3-7
Operation DMD15/DMD15L IBS/IDR Satellite Modem
3.8 Baseband Processor Card
The Baseband Processor Card (BB Card) contains two major subsystems⎯the Baseband
Processing System and the Monitor and Control Subsystem.
3.8.1 Baseband Processing
The Baseband Processor performs all of the functions required for an IBS/IDR Framing Unit, a
Reed-Solomon Codec, an E1/T1 Drop and Insert System and a Turbo Codec. In addition, the
Baseband Processing Section provides for Transmit clock selection and rate adaptation as well as
a rate adapter and Plesiochronous/Doppler (PD) Buffer in the receive direction. A multiplexer is
also provided for the SCT Clock Source for Loop Timing Applications. The transmit and receive
paths may be configured independently under processor control.
3.8.2 Tx Baseband Processing
As shown in Figure 3-7, the Tx Data and Clock enters the Baseband Processor, passes through a
Rate Adapting FIFO and enters the Framer/Drop Processor. In Closed-Net Mode, the data
passes through the framer unaltered. In IDR, IBS, and D&I Modes, the framer adds the
appropriate framing and ESC as defined in IESS-308 and 309. In D&I Mode, the framer acquires
the terrestrial framing structure, E1 or T1, and synchronizes the Drop Processor. The Drop
Processor extracts the desired time slots from the terrestrial data stream and feeds these
channels back to the framer. The framer then places the ‘dropped’ terrestrial time slots into the
desired satellite channel slots. The data is then sent to the Reed-Solomon Encoder.
The Reed-Solomon Encoder, if engaged, is designed as an installable option that encodes the
data into Reed-Solomon Blocks. The blocks are interleaved and synchronized to the frame
pattern as defined in IESS-308 and IESS-309. After Reed-Solomon Encoding, the composite
data and clock are applied to the BB Loopback Circuit.
Figure 3-7. DMD15/DMD15L Clock Logic
3-8 TM051 – Rev. 5.8
DMD15/DMD15L IBS/IDR Satellite Modem Operation
3.8.3 Rx Baseband Processing
The Receive Processor performs the inverse function of the Tx Processor. Data received from
the satellite passes through the BB Loopback Circuit to the Reed-Solomon Decoder to the
Deframer. The Deframer acquires the IBS/IDR frame, synchronizes the Reed-Solomon Decoder
and extracts the received data and overhead from the frame structure, placing the data into the
PD Buffer, sending the overhead data to the UIM. In Closed-Net Mode, the data is extracted from
the buffer and is sent to the UIM. Backward Alarm indications are sent to the M&C Subsystem.
In Drop and Insert Mode, the Insert Processor synchronizes to the incoming terrestrial T1/E1 Data
Stream, extracts satellite channels from the PD Buffer, and then inserts them into the desired
terrestrial time slots in the T1/E1 Data Stream.
3.8.4 Clock Selection
Both the Tx Clock and the Buffer Clock source may be independently locked to one of the
following:
Additionally, for loop timing applications the SCT Clock Source can be selected to be Rx Satellite
Clock.
3.9 Monitor & Control (M&C) Subsystem
Also contained on the BB Card is the M&C Subsystem. The M&C contains a high-performance
Motorola 68302 Microprocessor and is responsible for overall command and control of modem
functions. The M&C is constantly monitoring all subsystems of the modem by performing a
periodic poll routine and configures the modem by responding to commands input to the system.
During each poll cycle, the status of each of the subsystems is collected and reported to each of
the external ports and Front Panel. Performance statistics such as E
compiled. If faults are detected, the M&C will take appropriate actions to minimize the effect of
such faults on the system (Refer to the Fault Matrices in the Section 6 (Maintenance) of this
manual).
The M&C subsystem contains the following features:
, buffer fill %, etc. are
b/No
3.9.1 Asynchronous Serial Port #1
This port is dedicated to the Terminal Program. With this program, all features of the modem may
be controlled and monitored by any common terminal connected to the Terminal Port.
3.9.2 Serial Port #2
This port is dedicated to the Modem Remote Port. This port may be configured to support a
number of synchronous or asynchronous protocols such as HDLC, and RS-485. This port is
intended for use in computer-based remote M&C. All functions of the modem may be monitored
and controlled from this port.
3.9.3 Serial Port #3
This port is dedicated for ES-ES Communications. The port may be configured for a number of
communications protocols. Overhead data to/from the UIM is routed to/from the framer/deframer.
TM051 - Rev. 5.8 3-9
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