Nortel Networks Circuit Card 311 User Manual
Page 607
Operation
607
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 163 "Ground start call states - outgoing call to
and
Figure 164 "Ground start call connection
sequence - outgoing call to CO/FX/WATS" (page 609)
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.
This biases the tip ground detector OFF until the CO places ground on
the tip at seizure. After the tip ground is detected, the Universal Trunk
Card scans for a ringing detection signal before presenting the call to an
attendant and tripping the ringing. A low resistance is placed across the tip
and ring conductors and a speech path is established.
For outgoing calls, the trunk provides 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 Meridian 1 in the form of loop (interrupting) dial pulses or
DTMF tones. See
Figure 165 "Ground start call states - outgoing call to
and
Figure 166 "Ground start call connection
sequence - outgoing call to CO/FX/WATS" (page 611)
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311
01.04
Standard
Release 5.0
23 May 2008
Copyright © 2003-2008, Nortel Networks
.