Transmission Interface Handling DS1 1544 kbit/s
DS1 longhaul, 0 dB output.
The parameters can be modified from OMT. The new setting is
activated immediately. Thus, the updated parameters are used when the
selection of LBO is performed.
Two PCM paths are supported: PCM-A and PCM-B.
33.3.2
Layer 1 Termination Long Haul 1544 kbit/s
The function is initiated during restart of CMRU.
Layer 1 termination on the transport network interface includes:
•
Physical and electrical characteristics according to ANSI T1.403
(interface at 1544 kbit/s, one pair for each direction of
transmission, test load impedance 100
resistive), except the
receiver dynamic, see below.
•
Frame structure according to ANSI T1.403, ESF. T option only.
See Table 24 on page 200
8 traffic bits in all frames in the ESF.
•
Line coding B8ZS according to AT&T T1.107. B8ZS is the only
technology to provide 64 kb/s Clear Channel Capacity (64 CCC).
•
When no message is sent on the Data Link (DL, message bit m)
in the ESF, an idle pattern (01111110) (ref. ANSI 6.4(2)) is
transmitted. The datalink is used for RAI information in both
directions. See Table 24 on page 200
•
Frame alignment and CRC–6 procedures according to ANSI
TI.403, 24–frame ESF.
•
Fault supervision of each PCM path is performed according to:
−
ANSI T1.403 section 9 (1995)
−
AT&T T1.5, paragraph 7
This includes detection of the fault conditions LOF, LOS,
ERATE, AIS and RAI. It also includes a consequent action. The
consequent action for the faults LOF, LOS, ERATE, AIS and
UAST downlink is to send RAI patterns (...1111111100000000...)
continuously on the 4 kbit/s link to the remote end. This is
performed for at least one second.
Two PCM paths are supported: PCM-A and PCM-B. However PCM-B
can only be used when the function Multidrop (see chapter Channel
Distribution Function) is activated.
The receiver dynamic range for layer 1 transmission long haul is 0 to
-30 dB at 772 kHz (0 dB = 6.0 Vp-p, 100
twisted pair cables).
33.3.3
DS1/Layer 1 Synchronization
Synchronization of layer 1 is derived either from one of the incoming
PCM paths or taken from a free running oscillator.
The following cannot be used as a reference source:
EN/LZT 123 2697
R5A
1998-08-13
203 (306)
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— All Rights Reserved —
