Comtech EF Data CRS-120 - Manual (Page 40)

1:1 Redundancy Switch Revision 3
Summary Of Specifications MN/CRS120.IOM
5–4
5.2 1:1 Latching Operation
Table 5-3 explains two cases and how the health of 1:1 subsystem is monitored.
Event Mod A Mod B RF
Relay
Comments
Notes
Case 1
1 OK
(Online)
OK
(Standby)
A The online and standby units are designated. Tx IF = A 1, 2, 7, 8
2 Fault OK B A Faults and B is OK, switches to B. Tx IF = B 3, 4, 9, 10
3 Fault Fault B Fault in A and B. Tx IF = None (carriers muted by both modulators). 3, 4, 9, 10
4 OK Fault B Requires intervention. Tx IF = None (A is Standby and B carrier is
muted by modulator). 3, 4, 9, 10
5 OK OK B Requires intervention. Tx IF = B. 3, 4, 9, 10
Case 2
6 OK
(Online)
OK
(Standby)
A The online and standby units are designated. Tx IF = A 1, 2, 7, 8
7 OK Fault A A is OK and B Faults. Tx IF = A. 1, 2, 5, 6,
11, 12
8 Fault Fault A Fault in A and B. Switchover to a failed unit is not allowed. Tx IF =
None, and both carriers are muted. 1, 2, 5, 6,
11, 12
Notes:
Removal of the Alarm Cable while power is ON to both modulators:
1. Disconnecting the cable at A switches the B unit online and an alarm is reported.
Reconnecting the cable at A maintains the B unit online.
2. Disconnecting the cable at B keeps A online and an alarm is reported.
Reconnecting the cable to B keeps A online.
3. Disconnecting the cable at A maintains the B unit online and an alarm is reported.
Reconnecting the cable to A maintains the B unit online.
4. Disconnecting the cable at B maintains B online and an alarm is reported.
Reconnecting the cable to B keeps B online.
5. Disconnecting the cable at A maintains the A unit online and an alarm is reported.
Reconnecting the cable at A maintains the A unit online.
6.
Disconnecting the cable at B keeps A online and an alarm is reported.
Reconnecting the cable to B keeps A online.