
PEB 22554
Functional Description E1
Semiconductor Group
76
09.98
Table 8
Summary of Alarm Detection and Release
Alarm
Loss of Signal
(LOS)
Detection Condition
no transitions (logical
zeros) in a programmable
time interval of 16 - 4096
consecutive pulse periods.
Programmable receive
input signal threshold
FMR0.ALM = 0:
less than 3 zeros in
250 μsec and loss of frame
alignment declared
Clear Condition
programmble number of ones
(1-256) in a programmable time
interval of 16 - 4096 consecutive
pulse periods. A one is a signal
with a level above the
programmed threshold.
FMR0.ALM = 0:
more than 2 zeros in
250 μsec
Alarm Indication
Signal (AIS)
FMR0.ALM = 1:
less than 3 zeros in
each of two consecutive
250 μsec periods
bit 3 = 1 in time-slot 0 not
containing the FAS word
Y-bit = 1 received in CAS
multiframe alignment word
FMR0.ALM = 1:
more than 2 zeros in each of two
500 μsec periods
Remote Alarm
(RRA)
Remote Alarm in
Time-Slot 16
(TS16RA)
Loss of Signal in
Time-Slot 16
(TS16LOS)
Alarm Indication
Signal in Time-Slot 16
(TS16AIS)
set conditions no longer detected.
Y-bit = 0 received in CAS
multiframe alignment word
all zeros for at least 16
consecutively received
time-slots 16
time-slot 16 containing less
than 4 zeros in each of two
consecutive CAS
multiframes periods
more than 32 pulse periods
with highly increased
transmit line current on
XL1/2
32 consecutive zeros in the
transmit data stream on
XL1/2
receiving a one in
time-slot 16
time-slot 16 containing more than
3 zeros in each of two
consecutive CAS multiframes
periods
no transmit line current limiter
active
Transmit Line Short
(XLS)
Transmit Ones
Density
(XLO)
Cleared with each transmitted
pulse