Comtech CDM-625 Advanced LDPC Satellite Modem

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Comtech CDM-625 Advanced LDPC Satellite Modem is available to buy in increments of 1

Advanced Satellite Modem with variable rate from 18 Kbps to 25 Mbps

CDM-625 Advanced LDPC Satellite Modem

The CDM-625 Advanced Satellite Modem builds on Comtech EF Data’s legacy of providing the most efficient satellite modems. It is the first modem to combine advanced Forward Error Correction (FEC) such as VersaFEC and Low Density Parity Check (LDPC) codes with the revolutionary DoubleTalk Carrier-in-Carrier bandwidth compression, allowing for maximum savings under all conditions.

This combination of advanced technologies enables multi-dimensional optimization, allowing satellite communications users to:

  • • Minimize operating expenses (OPEX)
  • •  Maximize throughput without using additional transponder resources
  • •  Maximize availability (margin) without using additional transponder resources
  • •  Minimize capital expenses (CAPEX) by allowing a smaller BUC/HPA and/or antenna
  • •  Or, a combination to meet specific business needs

CDM-625 Carrier-In-Carrier Double Talk Diagram


•DoubleTalk Carrier-in-Carrier bandwidth compression 

• Carrier-in-Carrier Automatic Power Control 

• Adaptive Coding and Modulation (ACM)

• Packet Processor with header compression, payload compression, advanced Quality of Service (QoS) and Managed Switch mode

• 4-port managed Ethernet switch with VLAN and QoS 

• Jumbo frame support • Dual Band Capability: 70/140 MHz and L-Band in same unit 

• Data Rate: 18 kbps to 25 Mbps 

• Symbol Rate: 18 ksps to 12.5 Msps • Modulation: BPSK, QPSK/OQPSK, 8PSK/8-QAM, 16-QAM 

• FEC: Viterbi, Sequential, Concatenated Reed Solomon, TCM, Turbo Product Code (TPC) (IESS-315 Compliant), LDPC Code and VersaFEC (low-latency LDPC)

• Widest Range of data interfaces: EIA-422/530, V.35, G.703 T1, G.703 E1, G.703 T2, G.703 E2, Quad G.703 E1, ASI, LVDS, HSSI, 4-port 10/100Base-T Ethernet

• IEEE 1588v2 Precision Time Protocol 

• Sub Mux to multiplex IP/Ethernet traffic with serial or G.703 traffic

• Drop & insert for T1/E1 • Enhanced D&I++ for single T1/E1 & quad E1

• Management: 10/100Base-T Ethernet with SNMP, Distant End SNMP Proxy, HTTP, Telnet and EIA-232/EIA-485

• Embedded Distant-end Monitor and Control (EDMAC)

• Automatic Uplink Power Control (AUPC) • Engineering Service Channel (ESC/ESC++)

• Standard high-stability internal reference (± 6 x 10-8)

• 5-tap Adaptive Equalizer • L-Band TX: 10 MHz reference for BUC, FSK communications and optional BUC power supply

• L-Band: Advanced FSK for LPOD M&C

• L-Band RX: 10 MHz reference and LNB power supply • Open network modes • 1:1 and 1:10 redundancy switches available

Comtech CDM-625 Specifications

Common Applications

• Mobile Backhaul
• G.703 Trunking
• IP Trunking
• Offshore & Maritime Communications
• Enterprise
• Communications on the Move
• Satellite News Gathering