Functions - Ericsson CME 20 R6.1 Reference Manual

Figure 39
CMRU
For further information, see ITU-T G.704 White Book.
32.3

Functions

32.3.1 Layer 1 Termination 2048 kbit/s, 75 Ohm
The function is initiated during restart of CMRU.
Layer 1 termination of the transport network interface is handled
according to /GSM:08.54:4.0.0/. This includes :
•
•
•
•
•
EN/LZT 123 2697 R5A
1998-08-13
Transmission Interface Handling G.703 2048 kbit/s
Transport network
BSC
Upstream and Downstream
Physical and electrical characteristics according to ITU-T rec.
G.703 (interface at 2048 kbit/s, 75 ohm and over-voltage
protection according to Annex B)
Frame structure according to ITU-T rec. G.704 section 2.3
(includes handling of the E-bit in timeslot 0)
Frame alignment and CRC-4 procedures according to ITU-T rec.
G.706 section 4
Synchronization of layer 1 handling is described in Section 32.3.3
on page 190.
Detection of fault conditions, alarm states, and consequent actions.
This includes detection of:
−
LOS (Loss Of Signal)
−
LOF (Loss Of Frame alignment)
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RBS 1
DXB
PCM-A
PCM-B
RBS 2
DXB
PCM-A
PCM-B
Central Main Replaceable Unit. An RBS
has exactly one CMRU. In the RBS 2000
hardware architecture the Distribution
Switch is the CMRU.
01_0428A
189 (306)