Service Manual

GSM-204-323

Overview of digital modules

31st Oct 01

Technical Description: Horizon

macro

outdoor

68P02902W02-A

CONTROLLED INTRODUCTION

Tech. 6–1

Overview of digital modules

Overview and

redundancy

Digital modules provide the equivalent of M-Cell

micro base control unit

(µBCU) functionality for the Horizon

macro.

They are located in the bottom right

side of the main cage, and are electronically interconnected through the

backplane. Fibre optic connections are at the front of the appropriate modules.

Each digital module is assigned A or B, with one BPSM for A and one BPSM for

B. The alarm module is not assigned to A or B, as it is supplied by both BPSMs

for redundancy.

The master MCUF is assigned to A, and the redundant MCUF to B, each with

an associated FMUX.

The four NIUs are used by the operational MCUF, but two NIUs are powered by

BPSM A and two NIUs by BPSM B.

All slots are annotated with the legend of the appropriate module and located as

shown in Figure 6-1.