
CRS-280/280L IF Switch for 1:N Redundancy
Revision -
Introduction
1–2
MN-CRS-280/280L
The CRS-280 (70/140 MHz) IF Switch (Figure 1-1) provides complete isolation of the IF signals.
The Redundant Modem’s IF signals are routed to the Traffic Modem’s IF path when the Switch
RMI is online. The Switch automatically senses the presence of the CRS-280. The Switch, upon
switching, leaves the offline modem with its IF on, and the CRS-280’s relays isolate any
undesired signals.
The CRS-280 (70/140 MHz) IF Switch is necessary when one or more modems within the
redundancy system connect to more than one up/down converter. This occurs when the modems
connect to more than one transponder on the same antenna polarization, or when modem
redundancy needs to span two or more polarizations or antennas.
The CRS-280L (L-Band) IF Switch (Figure 1-2) is designed to support redundancy systems
featuring one Redundant (backup) Modem and up to 10 Traffic Modems (prime channels).
Operation of the CRS-280L is controlled by the switching system to which it is connected.
The CRS-280L (L-Band) Switch is necessary when one or more modems within the redundancy
system connect to the other polarization of the antenna or to multiple antennas.
The CRS-280/280L is designed for use with the following Comtech EF Data products:
Table 1-1. IF Switch Compatibility Table
Modem
Remarks
Max 1:N Redundancy
CDM-570L/570AL
Used with CRS-300 or CRS-500
1:10
CDM-600L
Used with CRS-300 or CRS-500 w/CRS-350 (ESC only)
1:10
CLM-9600L
CDM-600/600L
CDM-625/625A
CDM-700
CDM-710
CDM-710G/710GL
CDM-Qx/QxL
SLM-5650/5650A
SDM-300L3**
Used with SMS-7000**
1:8
SDM-2020D**
(L-Band)
Used with CRS-400 (HSSI)**
1:10
** Indicates a Comtech EF Data legacy product that is no longer in production
The CRS-280 replaces the following Comtech EF Data active or legacy products:
•
CRS-282 IF switch for 70/140 MHz applications
The CRS-280L replaces the following Comtech EF Data active or legacy products:
•
IFU for SMS-7000 L-Band applications.
•
CRS-282 IF switch for L-Band applications (CRS 300/CRS 500)
Summary of Contents for CRS-280
Page 28: ...CRS 280 280L IF Switch for 1 N Redundancy Revision Introduction 1 14 MN CRS 280 280L Notes ...
Page 68: ...CRS 280 280L IF Switch for 1 N Redundancy Revision Appendix B B 8 MN CRS 280 280L BLANK PAGE ...
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