The CRS-311 1:1 Redundancy Switch supports automatic or manual 1:1 protection for the Comtech EF Data 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.
The switch has two power supply modules. Each power supply provides the full demand for the switch, providing power supply
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.
The front panel of the switch contains the following items:
Unit Status LED
Stored Event 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
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.