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, CDM-710G 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 Bridge Mode
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 (PSUs).
Power consumption is so low, even for fully populated units, that no fan cooling is required.
1:N, maximum N = 10
Number of Uplink/Downlink Channels
10 maximum for CRS-300
8 maximum for SMS-7000
Tx/Rx Operating Frequency
950 to 1950 MHz
N-Type female (50 Ohm)
Tx Return Loss,
15dB at 50 Ohm
Tx to Tx Channel Isolation
Rx to Rx Channel Isolation
Tx to Rx Channel Isolation
Transmit IF Loss/Flatness
Tx In To Tx Uplink Out
BU In To Any Uplink Out
< 0.8 dB/0.5 dB over operating frequency
< 2.5 dB/1.0 dB over operating frequency
Receive IF Loss/Flatness
Rx Downlink In To Rx Out
Any Downlink In To BU Out
< 4.0 dB/0.5 dB over operating frequency
< 5.5 dB/1.0 dB over operating frequency
Rx Return Loss
15 dB into 50 Ohm
Power Loss Failsafe
All uplinks/downlinks revert to associated
CRS-xxx Type Switches
SMS-xxxx Type Switches
25 pin sub-D female
15 pin sub-D female
ENVIRONMENTAL & PHYSICAL
Prime Power, AC
100 to 240 VAC, 50 to 60 Hz, 40W maximum
19W x 14D x 7H inch (4 RU)
(48.2 cm x 35.6 cm x 17.8 cm)
< 25 lbs. (11.4 kg)
0 to 50°C (32 to 122°F)
-40° to +70°C (-40° to +158°F)