Radyne DMD2401 IBS 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 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 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
TM065 - Rev. 3.3 iii
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,
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.
2. 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 ComStream Corporation reserves the right to revise the foregoing list of what is covered
under this warranty.
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.

Warranty Policy DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem
TM065 – Rev. 3.3iv
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.

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Record of Revisions
TM065 - Rev. 3.3 v
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 Date Reason for Change
1.0 7-18-97 Preliminary Release
2.0 3-1-99 Added IBS/IDR Update information; New Interfaces Section; Updated
Remote Spec.
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.

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem
TM065 – Rev. 3.3vi
This Page is Intentionally Left Blank

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Table of Contents
TM065 - Rev. 3.3 vii
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

Table of Contents DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem
viii TM065 - Rev. 3.3
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

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Table of Contents
TM065 - Rev. 3.3 ix
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

Table of Contents DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem
x TM065 - Rev. 3.3
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

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Table of Contents
TM065 - Rev. 3.3 xi
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

Table of Contents DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem
xii TM065 - Rev. 3.3
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

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Table of Contents
TM065 - Rev. 3.3 xiii
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

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Introduction
TM065 - Rev. 3.3 1-1
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 user-
friendly 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 4800 bps –
1250 Kbps N/A 7200 bps – 1875 Kbps 8400 bps – 2187.5 Kbps
QPSK 9600 bps –
2500 Kbps N/A 14400 bps – 3750 Kbps 16800 bps – 4375 Kbps
OQPSK 9600 bps –
2500 Kbps N/A 14400 bps – 3750 Kbps 16800 bps – 4375 Kbps
8PSK N/A Optional N/A N/A
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.

Introduction DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem
1-2 TM065 – Rev. 3.3
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 IESS-
308/-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).

DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Introduction
TM065 - Rev. 3.3 1-3
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

Introduction DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem
1-4 TM065 – Rev. 3.3
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DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem Installation
TM065 - Rev. 3.3 2-1
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.