ZyXEL Communications Multi-service Access Platform MSAP2000 - Manual (Page 123)

7. Product Specification
MSAP2000 Technical Manual V3.0 7-16
7.7. Expansion Link Module (ELM)
Overview
The Expansion Link Module (ELM) co-works with the Expansion
Processing Module (EPM) to provide capacity expansion for a single
node. The ELM is installed within the main shelf, whereas the EPM is
installed within the extension shelf. The ELM’s functions are similar
to the OIM’s; the only difference being that the ELM’s optical emission
power is lower.
Features
And
Benefits
„ Panel LEDS indicate status, faults, alarms, and network connection
status
„ Timing recovery circuit, with ultra-low jitter
„ Simplified insertion and monitoring procedures for STM-1Overhead
Byte
„ Protection Switch functions
„ Alarm and fault monitoring and reporting
„ Digital cross-connection for all STM-1 Timeslots
„ Use of non-volatile memory devices for storage of performance
data
Function Diagram
Application
When more than one shelf in one node is needed, ELM must be
installed in the main shelf and with a corresponding EPM in the
expansion shelf. A Multi-mode optical patch cord must be used to link
between ELM and EPM.
ELM MPM Module
Local node communication
Module EPM Module
Local node communication