Service manual

B-6
Alarm sequence 2
B
Alarm handling
◆
Alarm sequence 2
Alarm states in
sequence 2
The following figure shows the various states in alarm sequence 2:
Behavior The following table shows the behavior of LEDs and relays in alarm sequence 1:
Alarm sequence 2
characteristics
The following table shows the characteristics of alarm sequence 2:
Reference Alarm sequence 2 complies with Bw 7R (FTZ 15281 Pfl 1) specified by Deutsche
Telekom.
0
No Alarm
1
Alarm
without Attn.
Alarm active
Alarm inactive
2
Alarm
with Attn.
Receive
Attention
Alarm Sequence 2
Active alarms require attention.
Alarm LED A = A alarm(s) in state 1
Alarm LED B = B alarm(s) in state 1
Rec. Attn. LED = alarm(s) in state 2
A relay = A alarm(s) in state 1
B relay = B alarm(s) in state 1
Rec. Attn. Relay = alarm(s) in state 2
ZA relay = A alarm(s) in state 1 or 2
ZB relay = B alarm(s) in state 1 or 2
Alarm inactive
LED or relay Indication
Alarm LEDS Active alarms without attention.
Alarm relays Active alarms without attention.
Receiving Attention relay Active alarms with attention
Z
A
or Z
B
Active or inactive alarms
Alarm sequence 2 characteristics
Relays indicate unserviced alarms Yes
Relays indicate all alarms Yes
One relay indicates alarms with attention Yes
One relay indicates cleared alarms with attention No
Tight control over alarms with attention No
Clear relay indication of alarms with or without attention Yes
Relays are used to switch to backup systems during alarm
conditions
Yes