User Manual

Table Of Contents
DXU Distribution Switch Unit
1 Product Overview
This section describes the main functions of the DXU and the following DXU
variants:
DXU-01
DXU-03
DXU-11
1.1 Main Functions
The DXU has the following main functions:
Distribution Switch
Timing Unit (a timing reference for the RBS is generated by extracting the
synchronization information from the PCM link or from an internal source)
Collection of up to 16 external alarms (product dependent)
Multidrop
Local bus interface RS 485 (acts as master on the bus and communicates
with distributed main RUs)
PCM interface G.703 (transmission fault supervision)
OMT interface RS 232
A-bis link resource management
Control link concentration (LAPD signalling to the BSC)
SW storage for the entire RBS in non-volatile memory
Maintaining the Installation Database (IDB) integrated with the DXU (the
IDB contains information regarding the installed HW, each RU identity, its
physical position and related configuration parameters)
1.2 Variants
The three DXU models described in this document as the following:
DXU-01 With E1 (CEPT) PCM links (2 Mbit/s) without internal
frequency reference
DXU-03 With T1 PCM links (1.544 Mbit/s) with internal frequency
reference
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EN/LZT 720 0243 Uen R1A