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System Description
SC 553 Data Service Unit Features
The SC 553 DSU provides the following features:
•
Supports full T1 or Fractional T1 operation with operating speeds, assigned in multiples of 56
kbps or 64 kbps, from 56 kbps to 1.536 Mbps (24 DS0s at 64 kbps each).
•
Supports selectable Extended Superframe Format (ESF) and D4 Superframe Formats at the
network interface and the optional cascade port.
•
Provides configurable Auto Framing options at the network interface and the optional cascade
port to adapt the DSU automatically to ESF or D4 format
•
Supports unframed operation, running at 1.544 Mbps.
•
Can be housed in a rack-mounted SpectraComm shelf that accommodates up to 16 units (one
of which must be an SCM); a pair of shelves can be linked by ribbon cables to accommodate
up to 31 DSUs and 1 SCM.
•
Can be housed in a SpectraComm 2000 enclosure that holds two cards for rack-mount or wall-
mount installation (SC 2000 enclosure requires only one rack unit (RU) of vertical space when
rack-mounted).
•
Supports Simple Network Management Protocol (SNMP) network management, which
provides complete software control for configuration, alarm reporting, and diagnostic testing
capabilities.
•
Communicates with SNMP controller through a shelf-resident SpectraComm Manager (SCM)
card for comprehensive, non intrusive network management.
•
Provides terminal interface functions that are accessible, when installed in SpectraComm shelf,
through the shelf-resident SCM card using either a VT100-compatible ASCII terminal or a
computer running the Telnet protocol.
•
Supports direct-connect terminal interface for a VT100-compatible ASCII terminal when
installed in an SC 2000 enclosure.
•
Provides selectable transmit timing: Receive, Internal, Cascade, External (DTE), or Station
Clock.
•
Provides DTE interface that conforms to ITU-T V.35; supports EIA-530 interface when
equipped with optional plug-in card.
•
Supports optional T1 Cascade Port interface, configurable for DSX-1 or DS1 operation; with
cascade installed:
•
channelized DS0 bundle from DTE port can be directed either to network interface or to
Cascade Port.
•
can function as CSU with all network interface DS0s connected to Cascade Port.
•
can be set up with a second SC 553 DSU at its own site and two SC 553 DSUs at the
remote site in a redundant T1 application that reroutes DS0s in the event of a line failure;
this application is illustrated in
•
supports automatic fault recovery application in which cascaded DSUs are installed in a
ring arrangement.
•
Compatible with remote NMS 553 or SC 553 DSUs for transmission and reception of user data.
1-2
Figure
1-1.
SpectraComm 553 Fractional T1 DSU
Installation and Operation Manual
SC 553 Data Service Unit Features
076R155-000
Issue 7
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