Nortel Networks 553-3001-211 manual Call placed by Central Office, Central Office disconnect

NTCK16 Generic Central Office Trunk cards Page 783 of 894

Call placed by Central Office

The Central Office initiates a call by applying ringing between the tip and ring wires. If the call is answered, the ringing detector on the trunk card is switched out and a low resistance dc loop is placed between the tip and ring leads.

On trunks configured for battery supervision, the battery detector records the polarity of the tip and ring wires and sends an answer acknowledge signal to software.

Call placed by CS 1000S, CS 1000M, and Meridian 1

To initiate a call, the CS 1000S, CS 1000M, and Meridian 1 switches out the ringing detector and places a low resistance loop across the tip and ring leads. On trunks configured for battery supervision, the trunk card sends a seize acknowledge signal to software.

The system sends digits in the form of Dual Tone Multifrequency (DTMF) tones or pulse digits. When the far-end answers, the Central Office reverses polarity. If the trunk is configured for battery supervision, it sends a polarity reversal message to software.

Central Office disconnect

There are two ways the Central Office can disconnect the call:

•by applying busy tone toward the CS 1000S, CS 1000M, and Meridian 1. If the trunk card is configured to detect busy tone, it will send a disconnect message to software.

•by reversing battery. If the trunk card is configured to detect battery reversal, it will send a disconnect message to software. When the unit on the trunk card has been idled, the trunk card sends a release confirm message to software.

CS 1000S, CS 1000M, and Meridian 1 disconnect

The CS 1000S, CS 1000M, and Meridian 1 disconnects the call by removing the loop between the tip and ring leads and replacing the ringing detector. Trunks configured for battery supervision send a release confirm message to software.

Circuit Card Description and Installation