Chapter 1. Introduction; Overview; Figure 1-1. Crs-311 1:1 Redundancy Switch - Comtech EF Data CRS-311 Installation And Operation Manual

1.1

Overview

The CRS‐311 1:1 Redundancy Switch is an accessory product designed specifically
for the Comtech EF Data CDM‐Qx/QxL or SLM‐5650/5650A modems. Do not use
this product with any other equipment.
The Comtech EF Data CRS‐311 1:1 Redundancy Switch (Figure 1‐1) – also referred to throughout
this manual as "the Switch" – is a companion product for use with the Comtech EF Data
CDM‐Qx/QxL or SLM‐5650/5650A Satellite Modems.
The CRS‐311 is designed to continuously monitor a pair of modems in a 1:1 redundant
configuration. A 1:1 system comprises a Traffic Modem, a Redundant Modem, and the CRS‐311
1:1 Redundancy Switch. The CRS‐311 automatically switches data and IF signals from a failed
Traffic Modem to the Redundant Modem in the event of an equipment failure or undesired
traffic condition – traffic paths are fully protected, ensuring that such failures do not adversely
affect system availability.
For the CRS‐311 to operate correctly, the Traffic Modem and the Redundant Modem
must be of the same model, equipped with the same hardware options and
modules, the same firmware versions, and the same FAST features. Chapter 4.
MODEM, RMI/TMI, AND SWITCH CONFIGURATION addresses permitted firmware
version combinations.
Figure 1‐2 shows the system‐level block diagram of the CRS‐311 1:1 Redundancy Switch,
including the CRS‐281 IF Switch. A key feature of the CRS‐311 architecture is its ability to allow

Chapter 1. INTRODUCTION

Figure 1-1. CRS-311 1:1 Redundancy Switch
1–1