Service Manual

GSM-204-323
NIU
31st Oct 01
Technical Description: Horizon macro outdoor
68P02902W02-A
CONTROLLED INTRODUCTION
Tech. 6–15
NIU
Overview of NIU
The network interface unit (NIU) module provides two E1 or two T1 termination
links to the terrestrial network. The NIU E1/T1 outputs are connected to a T43 or
BIB board, depending on the impedance matching requirement of the customer
terrestrial circuits.
There are two types of NIU board, one for E1, one for T1. The NIU layout is
common to both E1 and T1, the only differences being in the associated crystal
oscillators and line matching resistor values.
An on-board NIU control processor provides network interface configuration and
supervision, controlled by the MCUF.
NIU locations
The cabinet may contain up to four NIU modules in the digital module shelf, as
shown in Figure 6-1. Two NIUs are located in the master (lower) part of the
cage. Two NIUs are in the redundant (upper) part of the cage, though these
upper NIUs are also used for non-redundant purposes.
An NIU in slot A0 supports two E1/T1 links.
An NIU in slot A1 supports one E1/T1 link.
An NIU in slot B0 supports two E1/T1 links.
An NIU in slot B1 supports one E1/T1 link.
NIU command
identity number
Each NIU is identified in the database by an identity number, from 0 to 3.
Table 6-3 shows the NIU slots and equivalent identity number.
Table 6-3 NIU slot and equivalent command identity
NIU (MSI) identity number
used in commands
NIU slot
0 A0
1 B0
2 A1
3 B1