
PEB 2255
FALC-LH V1.3
Functional Description E1
Data Sheet
94
2000-07
4.5.2
Auto Modes
Automatic remote alarm access
If the receiver has lost its synchronization a remote alarm can be sent automatically,
if enabled by bit FMR2.A
X
RA to the distant end. The remote alarm bit is set
automatically in the outgoing data stream if the receiver is in asynchronous state
(FRS0.LFA bit is set). In synchronous state the remote alarm bit is removed.
Automatic E bit access
By setting bit
X
SP.A
X
S status information of received submultiframes is automatically
inserted in E-bit position of the outgoing CRC Multiframe without any further
interventions of the microprocessor.
Automatic AIS to system interface
In asynchronous state the synchronizer enforces automatically an AIS to the receive
system interface. However, received data can be transparently switched through if bit
FMR2.DAIS is set.
Remote Alarm in
time slot 16 (TS16RA)
Loss of Signal in
time slot 16
(TS16LOS)
Alarm Indication
Signal in time slot 16
(TS16AIS)
Y
-bit
=
1 received in CAS
multiframe alignment word
all zeros for at least 16
consecutivelyreceivedtime
slots 16
time slot 16 containing less
than
4
zeros in each of two
consecutive CAS
multiframes periods
If
X
L1 and
X
L2 are
shortened for at least 32
pulses
;
pins
X
L1 and
X
L2
are forced into a high
impedance state
automatically, if bit
X
PM2.DA
X
LT is reset.
Y
-bit
=
0 received in CAS
multiframe alignment word
receiving a one in
time slot 16
time slot 16 containing more than
3 zeros in each of two
consecutive CAS multiframes
periods
After 32 consecutive pulse
periods the outputs
X
L1/2 are
activated again and the internal
transmit current limiter is
checked. If a short between
X
L1/
2 is still existing, the outputs
X
L1/
2 are switched into high
impedance state again. When the
short disappears pins
X
L1/2 are
activated automatically.
Cleared with each transmitted
pulse
Transmit Line Short
(
X
LS)
Transmit Ones Density
(
X
LO)
32 consecutive zeros in the
transmit data stream on
X
L1/2
Table 21
Alarm
Summary of Alarm Detection and Release (E1)
(cont’d)
Detection Condition
Clear Condition