Power Requirements; Foreign And Surge Voltage Protection; Architecture; Signaling Interface - Nortel Enterprise 1000 Reference Manual

Page 200 of 236

Power requirements

Foreign and surge voltage protection

Architecture

Signaling interface

Interconnection

Microprocessor

553-3023-211 Standard 1.00 June 2001
NTRB21 DTI/PRI/DCH TMDI card
The DTI/PRI obtains its power from the backplane, and draws less than
2 amps on +5 V, 50 mA on +12 V, and 50 mA on –12 V.
Lightning protectors must be installed between an external T-1 carrier facility
and the Succession CSE 1000 system. For public T-1 facilities, this protection
is provided by the local operating company. In a private T-1 facility
environment (a campus, for example), the NTAK92 protection assembly can
be used.
The NTRB21 circuit card conforms to safety and performance standards for
foreign and surge voltage protection in an internal environment.
The signaling interface performs an 8 Kbps signaling for all 24 channels and
interfaces directly to the DS-30X link. Messages transmitted in both
directions are three bytes long.
The interconnection to the carrier is by NTBK04, a 1.5 Mb 20 ft. carrier cable.
The NT8D97AX, a fifty-foot extension cable, is also available.
The NTRB21 is equipped with bit-slice microprocessors that handle the
following major tasks:
• Task handler: also referred to as an executive. The task handler provides
orderly per-channel task execution to maintain real-time task ordering
constraints.
• Transmit voice: inserts digital pads, manipulates transmit AB bits for
DS1, and provides graceful entry into T-Link data mode when the data
module connected to the DTI/PRI trunk is answering the call.
• Receive voice: inserts digital pads and provides graceful entry into T-
Link data mode when the data module connected to the DTI/PRI trunk is
originating the call.