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DS1 I/O Rear Module
Plexus 9000 Planning and Engineering Guide
Issue 3, April 23, 2004
Section 130-120-450
5-128
Telica,
Inc
5.10.3 Theory
of
Operation
The rear DS-1 IOM has an EEPROM that contains the CLEI code, two 64-
pin connectors, line protection circuitry and relays that pass the DS-1s to
the front module or to the protection bus.
Front Card
Control
Protection Bus
MID
PLANE
Rear
Port #1
RX
Relay
Transformer
Lightning
Protection
Lightning
Protection
From Front Card
From Protection Bus
TX
Relay
Transformer
Control
Port #28
P251-AA
01-06-03
EE Prom
Figure 5.10-2. Block Diagram of Rear DS1 IOM
5.10.3.1 Power
Each DS1 I/O rear module receives its local voltages (5V, 3V, etc.) from
the front IOM that has the DC-to-DC converter for converting the -48
volts from the backplane. The power connection is not shown on the
block diagram.
5.10.3.2 Interface
Protection
Buses
Module protection is accomplished by the midplane design where the line
inputs can be routed from the working module to the protection module.
This is performed by relays on the working module that either connect the
signals straight through to the front module, or connect them onto the
midplane and the protection bus. The rear protection module picks the
signals off the midplane and routes them to the front protection module.