Comtech EF Data CRS-500 - Manual (Page 27)

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Chapter 1. INTRODUCTION
1.1 Overview
The CRS-500 is Comtech EF Data’s next generation 1:N Redundancy System. The modular
CRS-500 1:N Redundancy System (Figure 1-1) comprises a Control Switch Unit (CSU), Data
Switch Unit (DSU), and up to four optional CRS-282xx IF Switch Units (ISUs).
The CRS-500 is compatible for use with the Comtech EF Data CDM-625 Advanced Satellite
Modem equipped with the optional IP Packet Processor, and the Comtech EF Data CDM-750
Advanced High Speed Trunking Modem equipped with either Copper Gigabit Ethernet (also
referred to as GigE or GigE) or Copper E3/T3/STS-1. Intended for hub applications, the CRS-500
provides fully automatic or manual Traffic Modem protection of up to 10 Traffic (Prime)
Modems with one Redundant (Standby) Modem.
Figure 1-2 shows the system level block diagram of the CRS-500 1:N Redundancy System,
including the optional CRS-500 Tx/Rx ISUs. A key feature of the CRS-500 architecture is its ability
to allow the Redundant Modem to ‘bridge’ a Traffic Modem. You can configure the CRS-500 to
back up (replace) a Traffic modem when a Unit Fault and/or a Tx/Rx traffic Fault occurs. The
Redundant Modem locks to the Traffic Modem’s receive IF input signal, and the CRS-500
configures the Redundant Modem automatically to match the failed traffic modem’s
configuration.
You may also customize operation by selecting which Traffic Modem is the priority channel. The
operator can also program a delay interval for the Redundant Modem to wait before backing up
a failed Traffic Modem.
Because live traffic is used at all times to verify performance, no external test equipment is
needed to determine the health of the Redundant Modem.
The CRS-500 1:N Redundancy Switch is an accessory product designed specifically
for the Comtech EF Data CDM-625 Advanced Satellite Modem or the CDM-750
Advanced High Speed Trunking Modem. Do not use this product with any other
equipment.