Comtech EF Data CRS-300 - Manual (Page 88)

CRS-300 1:10 Redundancy Switch MN/CRS300.IOM
Cables and Connections Revision 19
4–14
4.3.2 IF Cable Connections – Multiple Transponder (Using IF Switch)
The CRS-280 IF (70/140 MHz) Switch 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.
Figure 4-7 provides a generic example of multiple transponder IF connections – in this instance,
a 1:1 configuration using a CRS-280 IF Switch with CDM-600 modems. Using PL/0946-2 (50Ω) or
PL/0813-8 (75Ω) BNC to BNC IF cables, observe the following for all modem/switch
configurations:
From the Redundant Modem:
• Connect the “Rx IF” BNC connector on the Redundant Modem to the BNC connector on the
CRS-280 switch labeled ‘TO REDUNDANT MODEM Rx’.
• Connect the “Tx IF” BNC connector on the redundant modem to the BNC connector on the
CRS-280 switch labeled ‘Tx FROM REDUNDANT MODEM’.
From the Tx Traffic Modems:
• Connect the “Rx IF” BNC connector on each Traffic Modem to a BNC connector on the CRS-
280 switch labeled ‘Rx # (where Rx # designates Rx 1 through Rx 10) TO TRAFFIC MODEM’.
• Connect the “Tx IF” BNC connector on each Traffic Modem to a BNC connector on the CRS-
280 switch labeled ‘Tx # (where Tx #designateis Tx 1 through Tx 10) FROM TRAFFIC
MODEM’.
When you use the CDM-Qx modem with the CRS-280 IF (70/140 MHz) Switch or the
CDM-QxL modem with the CRS-280L (L-Band) Switch, use no more than one Mod /
Demod per CDM-Qx/QxL chassis.
When you use the CRS-280L (L-Band) IF Switch, see the CRS-280L 1:N Redundancy
Switch Installation and Operation Manual (CEFD P/N MN/CRS280L.IOM) for
additional detailed installation information.