Comtech EF Data CDM-570A/L Satellite Modem

  • DoubleTalk Carrier-in-Carrier
  • Data rate range from 2.4 - 10.239 Mbps
  • Multiple Data Interface options
  • Automatic Uplink Power Control (AUPC)

Comtech EF Data CDM-570A/L Satellite Modem

The Comtech EF Data CDM-570A and the Comtech EF Data CDM-570AL are Comtech's next generation satellite modems that provide industry-leading performance and flexibility in a 1 RU package at a very competitive price. With support for VersaFEC® low latency LDPC Forward Error Correction (FEC), the revolutionary DoubleTalk® Carrier-in-Carrier® bandwidth compression, and optimized transmit filter rolloffs, the CDM-570A and CDM-570AL provide significant 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/amplifier and/or antenna
  • Or, a combination to meet specific business needs

The modems are available with 70/140 MHz or L-Band IF and EIA-530/-422, V.35, sync EIA-232 and G.703 T1/E1 data interfaces.

Comtech EF Data CDM-570A/L Features

  • DoubleTalk Carrier-in-Carrier bandwidth compression
  • VersaFEC low latency LDPC (Constant Coding & Modulation Mode)
  • 5%, 10%, 15%, 20%, 25% and 35% Transmit Filter Rolloff
  • Data rate range from 2.4 kbps to 10.239 Mbps
  • CDM-570A: 50 to 90 or 100 to 180 MHz IF range CDM-570AL: 950 to 2250 MHz IF range
  • Modulation types: BPSK, QPSK, OQPSK, 8PSK, 8-QAM, 16-QAM
  • Forward Error Correction (FEC) choices include VersaFEC, Turbo Product Code (TPC), Viterbi, Reed-Solomon, and Trellis Coded Modulation (TCM)
  • Data Interfaces: EIA-422/530, V.35, G.703 T1/E1, sync EIA-232
  • Standards based management via SNMP, Web, or Telnet
  • G.703 clock extension
  • Automatic Uplink Power Control (AUPC)
  • Embedded Distant-end Monitor and Control (EDMAC/EDMAC2)
  • 1:1 and 1:N Redundancy options
  • CDM-570A: FSK communications to CSAT-5060 or KST-2000A
  • CDM-570AL: 10 MHz reference for BUC, FSK communications and optional BUC power supply
  • CDM-570AL: 10 MHz reference and power supply for LNB

Typical Users

  • Enterprise
  • Internet Service Providers
  • Satellite Service Providers
  • Offshore & Maritime
  • Mobile Operators

Common Applications

  • Enterprise Networks
  • Offshore & Maritime Communications
  • obile Backhaul
  • Communications on-the-Move
  • Disaster Recovery & Emergency Communications
  • Satellite News Gathering

Doubletalk Carrier-in-Carrier

DoubleTalk Carrier-in-Carrier, based on patented “Adaptive Cancellation” technology, allows transmit and receive carriers of a duplex link to share the same transponder bandwidth. DoubleTalk Carrier-in-Carrier is complementary to all advances in modem technology, including advanced FEC and modulation techniques. As these technologies approach theoretical limits of power and bandwidth efficiencies, DoubleTalk Carrier-in-Carrier utilizing advanced signal processing techniques provides a new dimension in bandwidth efficiency. Figure 1 shows the typical full-duplex satellite link, where the two carriers are adjacent to each other. Figure 2 shows the typical DoubleTalk Carrier-in-Carrier operation, where the two carriers are overlapping, thus sharing the same spectrum.

When observed on a spectrum analyzer, only the Composite is visible. Carrier 1 and Carrier 2 are shown in Figure 2 for reference only.

As DoubleTalk Carrier-in-Carrier allows equivalent spectral efficiency using a lower order modulation and/or code rate, it can reduce the power required to close the link thereby reducing CAPEX by allowing a smaller BUC/amplifier and/or antenna. Alternatively, DoubleTalk Carrier-in-Carrier can be used to achieve very high spectral efficiencies E.g., DoubleTalk Carrier-in-Carrier when used with 16-QAM approaches the bandwidth efficiency of 256-QAM.

When combined with VersaFEC or TPC and optimized transmit filter rolloffs, DoubleTalk Carrier-in-Carrier provides unprecedented savings in transponder bandwidth and power utilization. This allows for its successful deployment in bandwidth-limited and power-limited scenarios, as well as reduction in earth station BUC/amplifier power requirements.

Carrier-in-Carrier Automatic Power Control (CnC-APC)

The patent-pending Carrier-in-Carrier Automatic Power Control (CnC-APC) mechanism enables modems on both sides of a CnC link to automatically measure and compensate for rain fade while maintaining the Total Composite Power. In addition to automatically compensating for rain fade, CnC-APC also enables the modems to share link margin, i.e. a modem can effectively transfer excess link margin to a distant end modem experiencing fade, thereby further enhancing overall availability.

VersaFEC Forward Error Correction

VersaFEC is a patent-pending system of high-performance LDPC codes designed to provide maximum coding gain while minimizing latency. CDM-570A/L support Constant Coding & Modulation (CCM) mode of operation.

The Ultra Low Latency (ULL) codes provide even lower latency compared to standard VersaFEC codes.

Optimized Transmit Filter Rolloffs

CDM-570A/L support 5%, 10%, 15%, 20%, 25% and 35% transmit filter rolloff allowing users to further optimize the link. Carrier-in-Carrier

combined with VersaFEC and optimized transmit filter rolloffs can provide 50% or more BW savings compared to legacy modems.

EDMAC & AUPC Operation

The Comtech EF Data CDM-570A/L-IP has the ability to monitor and control the distant end of a point-to-point satellite link using EDMAC or EDMAC2. User data is framed and bits are added to pass control, status, and AUPC information. This is transparent to the user.


The modems support SNMP, web-based and command line interfaces for management. The modems can also be configured and monitored from the front panel, or through the remote M&C port. Ten complete RF 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 (Eb/No and AUPC performance) for monitoring and reporting purposes.

FAST Feature Enhancements

The FAST codes make it easy to upgrade the modem capability in the field. New features can be added on site, using FAST access codes purchased from Comtech EF Data that can be entered via the front panel.

More Information
Country of ManufactureUnited States
ManufacturerComtech EF Data
Input Power100 - 240 VAC, -48VDC
Max Data Rate9.98 Mbps
Max Symbol RateN/A
Output Frequency70 MHz, 140 MHz
Warranty2 Years
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