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FALC
56
PEF 2256 H/E
Functional Description E1
User’s Manual
Hardware Description
93
DS1.1, 2003-10-23
4.3
Additional Receive Framer Functions (E1)
4.3.1
Error Performance Monitoring and Alarm Handling
Alarm Indication Signal: Detection and recovery is flagged by bit FRS0.AIS and
ISR2.AIS. Transmission is enabled by bit FMR1.XAIS.
Loss-Of-Signal: Detection and recovery is flagged by bit FRS0.LOS and ISR2.LOS.
Remote Alarm Indication: Detection and release is flagged by bit FRS0.RRA, RSW.RRA
and ISR2.RA/RAR. Transmission is enabled by bit XSW.XRA.
AIS in time slot 16: Detection and release is flagged by bit FRS1.TS16AIS and
ISR3.AIS16. Transmission is enabled by writing all ones in registers XS(16:1).
LOS in time slot 16: Detection and release is flagged by bit FRS1.TS16LOS.
Transmission is enabled by writing all zeros in registers XS(16:1).
Remote Alarm in time slot 16: Detection and release is flagged by bit FRS1.TS16RA and
ISR3.RA16. Transmission is enabled by bit XS1.2.
Transmit Line Shorted: Detection and release is flagged by bit FRS1.XLS and
ISR1.XLSC.
Transmit Ones-Density: Detection and release is flagged by bit FRS1.XLO and
ISR1.XLSC.
Table 21
Alarm
Loss-Of-Signal
(LOS)
Summary of Alarm Detection and Release (E1)
Detection Condition
No transitions (logical
zeros) in a programmable
time interval of 16 to 4096
consecutive pulse periods.
Programmable receive
input signal threshold
Alarm Indication
Signal (AIS)
less than 3 zeros in
250 μs and loss of frame
alignment declared
FMR0.ALM = 1:
less than 3 zeros in
each of two consecutive
250-μs periods
Remote Alarm
(RRA)
containing the FAS word
Clear Condition
Programmable number of ones (1
to 256) in a programmable time
interval of 16 to 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 μs
FMR0.ALM = 1:
more than 2 zeros in each of two
500-μs periods
FMR0.ALM = 0:
Bit 3 = 1 in time slot 0 not
Set conditions no longer
detected.