ZyXEL Communications Multi-service Access Platform MSAP2000 - Manual (Page 141)

7. Product Specification
MSAP2000 Technical Manual V3.0 7-34
7.13. STM-4 Module (SM4)
Overview
The STM-4 Module (SM4) provides standard SDH STM-4 optical
trunking, to connect to different Network nodes. Apart from data
transmission between different nodes, this Module also provides
SDH performance monitoring and fault reporting.
Features
And
Benefits
„ Panel LEDS indicate status, faults, alarms, and network
connection
„ STM- 4 optical Interface complies with ITU-T G.957 standards
„ Timing Recovery circuit, with ultra-low jitter
„ Insertion and monitoring of STM-4 Overhead Byte
„ Provides 1+1 protection switching
„ Protection switch mechanisms can be set-up, based on the
performance threshold value of the optical interface. Its
switch threshold (such as BER) can be either selected by the
User, or setup internally. In the event of protection switch
failure, an alarm warning will be shown.
„ Alarm and fault monitoring and reporting
„ Provides Digital cross-connect functions for all STM-4 time
slots
„ Synchronous clock timing for Main Power Modules
„ Use of non-volatile memory devices to store performance data
Function Diagram
Application
SM4 is used as the trunk interface and provide more bandwidth for
services. The pluggable optical transceiver allows user to use the
appropriate application code in the field without troubles.