Nortel Networks 553-3001-211 manual NT8D14 Universal Trunk card Page 569

NT8D14 Universal Trunk card Page 569 of 894

reverse-wired trunk becomes correctly wired, the first subsequent call clears the threshold counter and normal ground start processing is implemented.

Note 1: The far-end can reverse battery and ground upon receipt of attendant answer.

Note 2: The near-end provides a high-impedance (>150k ohms) disconnect signal of at least 50 ms before reconnecting the ground detector.

Outgoing calls

For outgoing calls, the trunk provides a ground to the ring lead. The CO responds by grounding the tip and returning dial tone. After the tip ground is detected by the card, a low-resistance path is placed between the tip and ring leads and the ground is removed from the ring. Addressing is then applied from the system in the form of loop (interrupting) dial pulses or DTMF tones. See Figure 118 on page 570 and Figure 119 on page 571.

The Polarity-Sensitive/Polarity-Insensitive Packs (PSP and PIP) feature must be set to provide for proper outgoing call-duration recording with ground start operation. Refer to the description of loop start operation in this section for a more complete discussion of PSP and PIP.

Circuit Card Description and Installation