
Specifications
CDM-600: 50 to 90 or 100 to 180 MHz,
CDM-600L: 950 to 2000 MHz,
100 Hz frequency resolution
CDM-600: 50 or 75 Ω (front panel
selectable)
CDM-600L: transmit 50 Ω, receive
50 or 75 Ω, female Type N connector
EIA-422/-530, V.35, Sync EIA-232,
G.703 balanced or unbalanced, Low
Voltage Differential Signal (LVDS), HSSI
(using CIC-20 HSSI/LVDS interface
Data Rate Range
(1 bps programmable, and fully independent TX and RX rates)
Turbo Product Coding Rates
7/8 16-QAM 16.8 kbps to 20.0 Mbps Turbo Card
Low Density Parity Check (LDPC) Rates
Mode dependent - ITU V.35 (Intelsat IESS-
308), or externally synchronized (Intelsat
IESS-309/-310/-314 or proprietary
Rate 1/2 BPSK, QPSK/OQPSK
Rate 3/4 and 7/8 QPSK/OQPSK and 16-QAM
Low-Rate TPC 21/44, 5/16 BPSK, and
High-Rate TPC 21/44, 5/16 BPSK,
1/2, 3/4, 7/8, 0.95 QPSK/OQPSK,
3/4, 7/8, 0.95 8-PSK, and 3/4, 7/8 16-QAM
LDPC 1/2 BPSK, 2/3, 3/4 QPSK/OQPSK,
2/3, 3/4 8-PSK, 2/3, 3/4 8-QAM, and
Intelsat compliant and proprietary modes
available
EIA-232, EIA-485 (2- or 4-wire)
TX, RX traffic alarms and unit faults
Backward alarms for IDR and IBS
Data Interfaces
G.703 (T1, E1, T2, E2), RS-422, V.35, LVDS or
Synchronous RS-232
(refer to manual for further information)
Supported
D4 or ESF for T1, CCS for E1
(Also CAS E1 for open network)
Available nx64 kbps
Data Rates
1 to 6, 8, 10, 12, 15, 16, 20, 24 or 30 for open
network, 1 to 24 for D&I++ enhanced proprietary
G.703 (T1, E1, T2, E2), RS-422, V.35, LVDS or
Synchronous RS-232
(refer to manual for further information)
Special features of the modems are their ability to monitor and control the distant end of a satellite link using a Comtech EF Data
proprietary overhead channel. This framed mode is called EDMAC. User data is framed and extra bits are added to pass control, status,
and Automatic Uplink Power Control information. This process is completely transparent to the user. An RF transceiver (C-Band and Ku-
Band) or Block Up Converter at the distant end of a satellite link may be controlled and monitored from the front panel of the modem
using a low data rate FSK signal on the RX IF cable via the EDMAC channel.
The operator may configure and monitor the modem from the front panel, or through the remote M&C port. Ten complete configurations
may be stored in the modem. An event log stores alarm and status information in non-volatile RAM, while the Link Statistics log stores
link performance (E
b
/N
o
and AUPC performance) for QoS reporting purposes. SatMac, a Windows-based monitor and control program, is
available for configuring the local and distant end modems, transceivers, and redundancy switches.
Low Density Parity Check (LDPC) Coding and 8-QAM Modulation
A third codec is available as a hardware option. The TPC/LDPC Codec combines all TPC functions of the High-Rate TPC option, plus the
following new features:
• Improved performance of LDPC codes at 1/2, 2/3, and 3/4 rates to further improve coding gain and bandwidth efficiency.
• 8-QAM modulation that offers the same bandwidth efficiency of 8-PSK but with improved BER performance and tracking in noisy
environments. The patented (U.S. patent 7,254,188) 8-QAM modulation was developed by Comtech EF Data in order to take full
advantage of the increased coding gain provided by LDPC, while allowing for acquisition and tracking at much lower Eb/No
Full drop and insert functionality is available as an option. The modems offer two variants of drop and insert (D&I). The first is an Intelsat
open network-compliant mode, using the IBS framing (6.7%). The second is CEFD’s proprietary enhanced mode, called D&I++. This “n” x
64 kbps mode offers any value of “n” up to 24, and permits the simultaneous use of EDMAC, AUPC (see below) and an ESC circuit at
1/576th of the user data rate. This is achieved with the addition of only 2.2% overhead.
A high rate overhead channel is now standard in the new enhanced version of the modems. This provides a separate RS-232 channel
allowing up to 4.8 kbaud at 64 kbps and up to 38.4 kbaud at 512 kbps. AUPC also operates in this mode.
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