Functional Description - Meridian Nortel 1 Option 11C Technical Reference Manual

Page 416 of 544

Functional description

553-3011-100 Standard 14.00
NT6D70 SILC line card
The SILC provides eight S/T four wire full duplex polarity sensitive
interfaces that are used to connect ISDN BRI compatible terminals over
Digital Subscriber Loops (DSL) to the Meridian 1. Each S/T interface
provides two B-channels and one D-channel and supports a maximum of
eight physical connections that can link up to 20 logical terminals on one
DSL.
A logical terminal is any terminal that can communicate with the Meridian 1
over a DSL. It may be directly connected to the DSL through its own physical
termination or be indirectly connected through a common physical
termination.
The length of a DSL depends on the specific terminal configuration and the
DSL wire gauge, however, it should not exceed 1 km (3,280 ft).
The SILC interface uses a 4 conductor cable that provides a differential
Transmit and Receive pair for each DSL. The SILC has options to provide a
total of 2 Watts of power on the Transmit or Receive leads, or no power at all.
When this power is supplied from the S/T interface, the terminal devices must
not draw more than the 2 Watts of power. Any power requirements beyond
this limit must be locally powered.
Other functions of the SILC are:
• support point-to-point and multi-point DSL terminal connections
• execute instructions received from the MISP to configure and control the
S/T interfaces
• provide channel mapping between ISDN BRI format (2B+D) and
Meridian 1 system bus format
• multiplexes 4 D-channels onto one timeslot
• perform activation and deactivation of DSLs
• provide loopback control of DSLs
• provide a reference clock to the clock controller
January 2002