Nortel Networks 553-3001-211 manual Micro Controller Unit MCU

NT6D70 SILC Line card Page 369 of 894

A logical terminal is any terminal that can communicate with the system over a DSL. It can 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 four-conductor cable that provides a differential Transmit and Receive pair for each DSL. The SILC has options to provide a total of two 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 two 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 system bus format

•multiplex 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

Micro Controller Unit (MCU)

The Micro Controller Unit (MCU) coordinates and controls the operation of the SILC. It has internal memory, a reset and sanity timer, and a serial control interface.

The memory consists of 32 K of EPROM which contains the SILC operating program and 8 K of RAM used to store interface selection and other functions connected with call activities.

Circuit Card Description and Installation