Comtech EF Data CRS-311 1:1 Modem Redundancy Switch System

CRS-311 1:1 Modem Redundancy Switch

The Comtech EF Data CRS-311 1:1 Redundancy Switch supports automatic or manual 1:1 protection for our SLM-5650A/5650 and CDM-Qx/QxL Satellite Modems. A CRS-281 IF redundancy module provides TX 70/140 MHz or L-Band backup. The switch connects two modems – a traffic unit and a redundant unit. It monitors the fault status of these two units. If there is an equipment failure, switching automatically takes place to protect the IF, data and overhead traffic circuits. The traffic and redundant modems are linked together so that any configuration changes made to the traffic unit are automatically updated in the redundant unit.

Functional Overview

The switch has two power supply modules. Each power supply provides the full demand for the switch, providing power supply redundancy. The 1:1 controller is within the CRS-311, providing control and driving signals for all switching. This unit continuously monitors a pair of modems so that, in the event of an equipment failure (or an undesired traffic condition), the sub-system automatically replaces the failed unit with the redundant unit.

Front Panel

 Unit Status LED

 Stored Event LED

 Remote LED

 Online LEDs: indicates which modem is carrying traffic

 Keypad: provides up, down, left, right, clear and enter operation in conjunction with the display

 Vacuum fluorescent display: 2 lines x 24 characters

RF Interface Panel

Located on the rear panel are several key items/assemblies. These include two CRS-241 AC power supplies or two CRS-251 DC power supplies for redundant prime power. A CRS-230 System Interface Controller supports the logic and switchover, and supplies a control interface to the CRS-311. A selection of Traffic Modem Interface (TMI) and Redundant Modem Interface (RMI) modules are available to support data switchover, and one of the two types of CRS-281 IF switches is available for either 70/140 MHz or L-Band redundancy. For the CDM-QxL, the CRS-281A is available to switch BUC and LNB DC power, 10 MHz and FSK.