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Comtech EF Data CDM570L L-Band Satellite Modem

The CDM-570L is a Closed Network modem, designed to meet the needs of low-cost terminals with L-Band interfaces to Low Noise Block Converters (LNBs) and Block Upconverters (BUCs).
  • G.703 Clock Extension for IP backhaul
  • Vipersat Management System (VMS) integration
  • IP Module with 10/100BaseT Ethernet port
  • 10/100BaseT Ethernet port for M&C with Web browser, SNMP and Telnet support
  • Interoperable with SDM-300A and SDM-300L3
  • Backwards compatible with the CDM-500/CDM-550, CDM-550T, CDM-600, and CDM-600L
  • CDM-570L: 10 MHz reference and power supply for LNB
  • CDM-570L: 10 MHz reference for BUC, FSK communications and optional BUC power supply
  • CDM-570: FSK communications to CSAT-5060 or KST-2000A
  • 1:1 and 1:10 redundancy switches available
  • Built-in 1:1 redundancy controller (Y-cables for data, simple and inexpensive external module for IF and RF)
  • Asymmetric Loop Timing
  • Embedded Distant-end Monitor and Control (EDMAC)
  • Automatic Uplink Power Control (AUPC)
  • Forward Error Correction (FEC) choices include Turbo Product Code (TPC), Viterbi, Reed-Solomon, and Trellis Coded Modulation (TCM)
  • Modulation types: BPSK, QPSK, OQPSK, 8-PSK, 8-QAM, 16-QAM
  • Fast acquisition demodulator (± 32 kHz acquisition range, 64 kbps, Rate 1/2 QPSK: 150 ms average)
  • CDM-570: 50 to 90 or 100 to 180 MHz IF range, CDM-570L: 950 to 1950 MHz IF range
  • Data rate range from 2.4 kbps to 9.98 Mbps

The CDM-570 and the CDM-570L are Comtech EF Data's entry-level satellite modems that provide industry leading performance and flexibility in a 1 RU package at a very competitive price. It is the platform of choice for Network Operators, Enterprise users, Service Providers, Broadcasters and Government users for a wide range of applications - Cellular Backhaul over IP, Voice-over-IP (VoIP), LAN/WAN connectivity, Satellite News Gathering (SNG), Communication-on-the-Move, Maritime, Offshore applications etc.

Designed to address the market for low-cost terminals, the modems are available with 70/140 MHz or L-Band IF and EIA-530/-422, V.35, EIA-232 and G.703 data interfaces. An optional Internet Protocol (IP) Module with 10/100BaseT Ethernet port is available for IP centric applications.

The advanced FPGA-based architecture along with the internal Flash memory allows for easy field upgrades via the Ethernet port.

Turbo Product Coding

The optional Turbo Product Codec delivers significant performance improvement when compared to Viterbi with concatenated Reed-Solomon. It offers increased coding gain, lower decoding delay, and significant bandwidth savings compared to traditional FEC.

EDMAC & AUPC Operation

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


The modem can be configured and monitored 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 nonvolatile RAM, while the Link Statistics log stores link performance (Eb/No and AUPC performance) for monitoring and reporting purposes.

The CDM-570/L also offers a 10/100BaseT Ethernet port for management with an embedded Web Server (HTTP), SNMP agent, and Telnet capability.

IP Module and Vipersat Networks VMS

With the optional IP Module, the CDM-570/L provides advanced features for IP networking including Quality of Service (QoS), Header and Payload Compression.

Optionally, it can also be integrated with the Vipersat Management System (VMS) to provide fully automated network and capacity management.

G.703 Clock Extension

Cellular networks require precise synchronization of base stations, which is a challenge when using IP backhaul. Most operators are forced to use GPS based external equipment for site synchronization.

CDM-570/L offers a G.703 Clock Extension option that propagates a high stability reference from Hub to the Remote. A high stability E1/T1 reference signal is fed to the Hub modem. The Remote modem generates a T1/E1 signal synchronized to the reference signal that is then used for synchronizing the Remote site. G.703 Clock Extension can be used with the IP Module or when using serial synchronous data interfaces. This process does not require additional bandwidth.

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.

CDM-570L Rear Panel

 IP Module & VMS Integration

With its innovative architecture and support for advanced capabilities, an IP-Module equipped CDM-570/L allows for efficient IP networking and transport over satellite links. It supports a wide range of applications and network topologies.

Key Features

  • easyConnect® for set up with minimal configuration
  • Static IP routing for unicast and multicast
  • Standards based management via SNMP, Web, or Telnet
  • IGMP v1 and v2
  • Symmetric as well as asymmetric operation for maximum bandwidth efficiency
  • Support for Mesh, STAR and hybrid network topologies

Data Encryption Option

Configurable on a per route basis, the IP Module supports 3xDES data encryption to prevent unauthorized access to data transmitted over the satellite link.

Quality of Service (QoS) Option

The IP Module supports multi-level QoS to reduce jitter and latency for real time traffic, provides priority treatment to mission critical applications and allows non-critical traffic to use the remaining bandwidth. Supported modes are:

  • DiffServ - Industry-standard method of providing QoS enabling seamless co-existence in networks that implement DiffServ.
  • Max/Priority - Provides 8 levels of traffic prioritization with the ability to limit maximum traffic per priority class
  • Min/Max - Provides a Committed Information Rate (CIR) to each user defined class of traffic with the ability to allow a higher burstable rate depending on availability

Header Compression Option

Configurable on a per route basis, Header compression reduces the bandwidth required for Voice over Internet Protocol (VoIP) by as much as 60%. Example: A G.729 voice codec, operating at 8 kbps, requires 32 kbps bandwidth once encapsulated into an IP/UDP/RTP frame. With IP/UDP/RTP header compression, the same voice call needs only 10.8 kbps total WAN satellite bandwidth. Typical Web/HTTP traffic can also be reduced by 10% via IP/TCP header compression.

Payload Compression Option

Configurable on a per route basis, Payload compression can reduce the required satellite bandwidth by up to 40%.

Networking Protocols

RFC 768 - UDPRFC 2045 - MIME
RFC 791 - IPRFC 2236 - IGMP v2
RFC 792 - ICMPRFC 2474 - Diffserv
RFC 793 - TCPRFC 2475 - Diffserv
RFC 826 - ARPRFC 2578 - SMI
RFC 856 - TelnetRFC 2597 - AF PHB
RFC 862 - PingRFC 862 - Ping
RFC 894 - IPRFC 2616 - HTTP
RFC 959 - FTPRFC 2821 - SMTP
RFC 1112 - IP MulticastRFC 3412 - SNMP
RFC 1213 - SNMP MIB IIRFC 3416 - SNMPv2
RFC 1812 - IPv4 RoutersRFC 3418 - SNMP MIB

VMS Network & Bandwidth Management

A Vipersat powered network integrates this advanced modem with a powerful network management tool, the Vipersat Management System (VMS). In addition to the traditional Monitoring and Control of the CDM-570/L modems, CDD-564/L and CDD-562L demodulators, the VMS allows these devices to share bandwidth, and when needed, switch automatically to a dedicated SCPC channel.

In a Vipersat powered network, the CDM-570/L modem takes advantage of its fast acquisition demodulation to allow it to operate in a shared mode. Inbound transmissions (from remote to hub) can be switched from a shared Selective Time Division Multiple Access (STDMA) mode to a dedicated Single Carrier Per Channel (SCPC) connection via a variety of user defined policies or triggers. This enables the network to more effectively handle real-time connection-oriented applications and reduces both latency and network congestion. Through VMS, dynamic point-to-point mesh connections can also be established between remotes.

  • Dynamic SCPC carrier allocation & true bandwidth-ondemand
  • User-defined policies for upstream carrier switching
  • Star and full mesh capabilities using Single Hop On Demand
  • Advanced Switching takes advantage of using other modulation/forward error correction combinations

Upstream Switching

Through protocol classification in the remote terminals, the modem initiates automatic switching. VMS establishes dSCPC bandwidth based on policies that can be individually enabled on a per-remote basis, or globally enabled. Policies can be configured for a variety of applications such as VoIP, video (VTC), or based on a load, or via a schedule, Type of Service (ToS), or QoS rules such as IP port or IP address and protocol type. Operators are able to set minimum and maximum data rates for each remote as well as excess data rates for an initial upstream switch.

Vipersat Operation Mode

Vipersat operation is enabled via a FAST feature code. Networks can easily start off in point-to-point or point-to-multipoint configurations. As the network grows and users wish to take advantage of the bandwidth on demand savings by implementing a Vipersat network, modems can easily be upgraded to Vipersat mode. Vipersat mode provides for the ability to operate in the following modulation/FEC rates:

STDMA     QPSK, Rate 3/4 Turbo FEC -                           all STDMA modes

                 Data Rate Range: 64 kbps -                            4.5 Mbps

                 BPSK, Rate 5/16 Turbo FEC -                          Entry Channel Mode only.

                 Data Rate Range: 32 kbps to 937                    kbps.


SCPC       All Turbo Product Code FEC rates