The CRS-300 1:10 modem redundancy switch provides fully
automatic or manual redundancy for the following modems: CDM-
570/570L, CDM-600/ 600L, CDM-625, CDM-Qx/QxL, CDM-700,
CDM-710, and SLM-5650A.
The protection system consists of a maximum of 10 traffic modems,
a redundant modem, and the CRS-300 redundancy switch. Two
companion (slaved) 1:N switches are also available: the CRS-280/
280L IF switch and the CRS-350 ESC switch. The IF switch is used
in multiple transponder applications. The CRS-350 is used for open
network ESC redundancy switching.
The CRS-300 supports a wide range of terrestrial data interface
types including: EIA-422/530, V.35, EIA-232, LVDS, G.703
(balanced or unbalanced), ASI, 10/100/1000 Ethernet and HSSI.
In many cases, each traffic modem can have a different
terrestrial data interface types.
Key Reliability Features
Twin, independent AC or DC power supplies
Passive backplane for signal path
Non-interruption of normal traffic upon power failure
Non-interruption of user data when other traffic modem
Interface circuit cards are removed
Data and clock provided to the redundant modem when in
Programmable holdoff times to backup or restore
Audible alarm programmable to activate, based on various
changes in status
Provides single-point remote Monitor and Control (M&C) to
switch and traffic modems
Simplified configuration and control
2 line x 24 character Vacuum Fluorescent Display
Front panel keypad
LED system status display showing unit and modem status,
online/offline status, and bridge status
The configuration of each traffic modem is stored in the CRS-
300 controller. This information is used to program the
redundant modem if the traffic modem fails. The modem
information is copied to the controller through a serial cable.
The CRS-300 also controls the traffic and redundant modem IF
output. All modem outputs are ON if the CRS-280 or CRS-280L
IF switch is used in the system. The downlink path through the
CRS-280/ CRS-280L is completely passive.
External monitor and control may be connected to the CRS-230
controller board. The CRS-300 and each traffic modem may be
monitored or controlled through this remote serial interface.
The data and clock signals to and from a traffic modem are routed
through a Traffic Modem Interface (TMI) via a set of relays. This
allows the data signals to pass directly through to the traffic
modem in the event of a power failure. If the system’s power
supplies are lost, or if a TMI carrying traffic is removed, no
interruption of traffic occurs.
The Bridge Mode may be used to verify the user data on a
specific traffic modem. The redundant modem locks to the traffic
modem receive IF input signal. The operator can program a
delay interval for the backup modem to wait before coming
online when a traffic modem failure occurs.
The redundancy switches are modular in construction. All
replaceable modules insert into slots in the back panel,
including the controller, Traffic Modem Interfaces (TMIs),
Redundant Modem Interfaces (RMIs), and Power Supply Units
Power consumption is so low, even for fully populated units,
that no fan cooling is required.
1:N redundancy switch system, N=10 max, bridging
C161 control processor
Fully automatic or manual
Force traffic modem to redundant modem
Force redundant modem to bridge traffic modem
Remove selected traffic modem from control
Programmable hold-off to backup and hold-off to restore from
0 to 99 seconds
Any one of the 10 traffic paths (bridge mode), both RX IF,
and TX data
Switch to redundant modem following a unit fault,
TX traffic alarm or RX traffic alarm
CRS-300 without CRS-280 IF switch; IF ON / OFF control
through the switch controller.
CRS-300 with CRS-280; all modem outputs on all the time.
7 seconds max (Delay interval set to zero)
25-pin "D" type male connector carrying data, alarm and
remote control signals
15-pin "D" subminiature type male connector
Vacuum fluorescent display, 2 lines, 24 characters, tactile keypad
LED system status display showing, for all modems:
Unit fault RX traffic alarm
TX traffic alarm on-line/off-line status
Can be programmed to activate following various changes of
Dry relay contacts
Two independent inputs:
100 to 250 volts AC, Autosensing
Fused IEC connectors, 25 Watts maximum
Dimensions and Weight
4U chassis - 10.8 in. deep (275 mm), 18.5 lbs. (8.4 kg.)
EMC and Safety
EN 55022 CLASS B (Emissions)
EN 50082-1 (Immunity)
EN 60950 (Safety) FCC Part 15 Class B