Nortel Networks 553-3001-211 manual 818 of 894 NTRB21 DTI/PRI/DCH Tmdi card

Page 818 of 894 NTRB21 DTI/PRI/DCH TMDI card

Foreign and surge voltage protection

Lightning protectors must be installed between an external T1 carrier facility and the system. For public T1 facilities, this protection is provided by the local operating company. In a private T1 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.

Functional description

NTRB21 provides the following features and functions:

•configurable parameters, including A-Law and µ-Law operation, digital pads on a per channel basis, and Superframe or Extended Superframe formats

•AMI or B8ZS line coding

•1.5 Mb Digital Trunk Interface and 1.5 Mb Primary Rate Interface

•1.5 Mb Clock recovery and distribution of reference clocks

•DG2 or FDL yellow alarm methods

•card status and alarm indication with faceplate-mounted LED

•automatic alarm monitoring and handling

•Card-LAN for maintenance communication

•loopback capabilities for both near-end and far-end

•echo canceler interface

•integrated trunk access (both D-channel and in-band A/B signaling can be mixed on the same PRI)

•faceplate monitor jacks for T1 interface

•configurable D-channel data rate with 64 kbps, 56 kbps or 64 kbps inverted

•self-test

553-3001-211 Standard 2.00 September 2004