Reference Manual

Transmission Interface Handling G.703 2048 kbit/s
The frame alignment word in time slot 0 even frames is used to
determine the error rate.
ERATE ceases
Detection of bit error ratio less than 10
–3
.
LOS commences
Three or less 1’s are received in a time interval of 250 µs.
LOS ceases
More than three 1’s are received in a time interval of 250 µs.
AIS commences
A continuous stream of 1’s during two frames. A limited number of 0’s
corresponding to BER = 10
–3
is allowed.
AIS ceases
Frame alignment signal is detected or recognised.
RAI commences
The A-bit (in timeslot 0) = 1.
RAI ceases
The A-bit (in timeslot 0) = 0.
UAST commences
UAST commences when unavailable state is declared. Each direction
(upstream and downstream) is supervised independently of the other.
An unavailable state for one direction is declared at the onset of P
consecutive SES for the direction of interest. These P seconds are
considered to be part of the unavailable time.
Together with the alarm status, time information for each direction of
UAST is reported to the BSC. When UAST commences, zero is
reported as time information. When UAST ceases, the time that the
UAST alarm has been activated is reported.
When the BSC requests the alarm status, two scenarios are possible:
UAST is activated and UAST is not activated. If it is activated, zero is
reported as time information. Otherwise, the time that the UAST alarm
was activated the latest time, is reported to the BSC.
UAST ceases
UAST ceases when available state is declared. Each direction (upstream
and downstream) is supervised independently of the other.
354 (421)
EN/LZT 720 0008 R1A
2001-06-26
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