INTRODUCTION
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1 INTRODUCTION
1. 1 About The FM4800
The FM4800 Data Service Unit (DSU) is used to connect high performance bridges and
routers to high speed 8Mbit/s services.
The FM4800 interfaces a E2 service (8.448 Mbit/s) and Data Terminal Equipment presenting
an X.21 interface.
FM4800 DSU’s are used in pairs, one at either end of a Wide Area Network (WAN) link. One
end is called the LOCAL node, and the other the REMOTE node.
The FM4800 also provides extensive performance monitoring facilities. It can monitor
degraded line performance and has extended alarm processing on the connection, giving
the network manager extensive visibility and control of the wide-area link.
A record of all error conditions, including major and minor alarms and bit errors, is kept for
the last 24 hours. Statistics are recorded every 15 minutes and processed into G.821 format.
Ninety-six 15 minute periods are kept, which means that 24-hour coverage is maintained on
a rolling basis.
Diagnostics are provided to localise a fault condition on the line. These are provided by
various types of loopback.
The FM4800 may be managed by connecting a video terminal to the unit, either directly
through a serial interface, or via a multiplexer or modem. With the optional LM1100 SNMP
Enabler the FM4800 can be managed remotely with a Simple Network Management
Protocol (SNMP) management system connected to the LAN. Telnet access can also be
achieved through the LM1100.
Finally, with a video terminal connected to the serial interface port, the FM4800 doubles as
a terminal adapter and connection may be made to remote Telnet-accessible devices via the
LM1100 SNMP Enabler.
