Q-Flex Satellite Modem Installation and Operating Handbook
10-9
Backward Alarms
Pin
Number
Description
1
BA 1-4 Common
2
BA1 N/O
18
BA1 N/C
3
BA2 N/O
19
BA2 N/C
4
BA3 N/O
20
BA3 N/C
5
BA4 N/O
21
BA4 N/C
22
BA1 Input
23
BA2 Input
24
BA3 Input
25
BA4 Input
7
Rx Summary fault output (link to BA in)
6
Ground
N/O indicates normal open in the normal, non-alarm state & N/C normally closed in the
non-alarm state. Unlike the modem fault relays, the backward alarms are not normally
energised, and fall back to the `Normal` state when modem power is removed. The
modem deferred alarm acts as a summary backward alarm and activates when any
backward alarm is received (this does fall back to the `Fail` state when power is
removed).
Backward alarm inputs float to the `Good` state (high =+5V) and indicate `Fail` when
connected to 0V. The Rx summary fault is an open collector output, 0V = Fail, open
collector=OK. From the front panel the backward alarm inputs (BA x)can be set as follows
(E=Ext, A=Auto-Rx fail, O=OK):
Menu Opt BA 1
BA 2
BA 3
BA 4
Mode 1
EEEE
Ext patch Ext patch Ext patch Ext patch
Mode 2
AEEE
Rx Fail
Ext patch Ext patch Ext patch
Mode 3
AOOO
Rx Fail
Good
Good
Good
Mode 4
AAAA
Rx Fail
Rx Fail
Rx Fail
Rx Fail
If external patching is required, connect the Rx summary fault to the required BA input
and any other modem fail outputs to the appropriate other BA inputs. Leave unused
inputs floating.