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FALC
56
PEF 2256 H/E
Functional Description E1
User’s Manual
Hardware Description
94
DS1.1, 2003-10-23
4.3.2
Auto Modes
4.3.2.1
Automatic Remote Alarm Access
If the receiver has lost its synchronization a remote alarm can be sent automatically, if
enabled by bit FMR2.AXRA 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.
4.3.2.2
Automatic E-bit Access
By setting bit XSP.AXS status information of received submultiframes is automatically
inserted at the E-bit position of the outgoing CRC Multiframe without any further
interventions of the microprocessor.
4.3.2.3
Automatic AIS to System Interface
In asynchronous state the synchronizer enforces an AIS to the receive system interface
automatically. However, received data can be switched through transparently, 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
consecutively received time
slots 16
Time slot 16 containing less
than 4 zeros in each of two
consecutive CAS
multiframes periods
More than 3 pulse periods
with highly increased
transmit line current on
XL1/2
32 consecutive zeros in the
transmit data stream on
XL1/2
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 one CAS multiframe
Transmit Line Short
(XLS)
Transmit line current limiter
inactive
Transmit
Ones-Density
(XLO)
Cleared with each transmitted
pulse
Table 21
Alarm
Summary of Alarm Detection and Release (E1)
(cont’d)
Detection Condition
Clear Condition