Comtech EF Data CRS-500 1:N Modem Redundancy Switching System

CRS-500 1:N Modem Redundancy Switch

The Comtech EF Data CRS-500 is a cutting edge next generation 1:N Modem Redundancy System. Intended for hub applications, it provides automatic or manual protection for up to 10 Traffic (or prime) modems with one redundant (or standby) modem. The CRS-500 supports the CDM-625/625A, CDM-760 and CDM-750 modems for select interfaces. The CDM-625/625A is supported when using the 10/100 Packet Processor mode. The CDM-750/760 is supported when using the ASI, G.703, Gig-E native interface or Gig-E Packet Processor interface (packet processor and ASI only available on the CDM-760). As shown in the figure, the CRS-500 is a flexible, modular-type architecture, composed of a Control Switch Unit (CSU), Data Switch Unit (DSU) and optional IF Switch Units (ISUs). A key feature of the CRS-500 architecture is its ability to allow the redundant modem to ‘bridge’ a traffic modem. The CRS-500 controller automatically configures the redundant modem to match the bridged traffic modem’s configuration. The CRS-500 also provides a copy of the bridged traffic modem’s TX traffic data to the redundant modem. When using the IF Switch Units (ISUs), it additionally routes the bridged traffic modem’s RX IF.

Key Features

• Flexible 1:10 (max.) configuration 
• Primary traffic paths are maintained, error-free, when power is removed 
• Non-interruption of traffic data when Traffic Modem Interface (TMI) cards are removed 
• Bridge mode (hot-standby) redundant modem to ensure quick availability for backup 
• Programmable hold-off times to backup or restore 
• Programmable preference Selectable Prime Traffic Modem 
• Remote (Ethernet or serial) Monitor and Control to switch 
• Multiple user interfaces (Web/HTTP, SNMP, MIB, Front panel) 
• LED summary panel showing switch and modem status, bridge and online/offline 
• Dual independent & hot-swappable/uninterrupted AC or DC power supplies 
• Audible alarm programmable to activate, based on various changes in status

Control Switch Unit

The CSU is the controller of the CRS-500 Redundancy System and consumes only 1RU of rack space. It contains field-replaceable modules such as the CRS-530 controller and dual, hot-swappable Power Supply Units (PSUs). The configuration of each traffic modem is stored in the CRS-530 controller. This information is used to program the redundant modem if a traffic modem fails. The CSU contains an extensive M&C system and is fully controllable from the front panel or from external 10/100 Ethernet or EIA-232C/485 ports located on the back side of the CSU unit, (on the CRS-530 module). Ethernet is used by the switch to communicate to all modems. A 10/100 Ethernet M&C connection goes to/from each modem to the CSU.