Nortel Networks 1000 - Manual (Page 507)

Operation 507
detects the low-resistance loop, it prepares to receive digits.When the CO
is ready to receive digits, it returns a dial tone. Outward address signaling
is then applied from the system in the form of loop (interrupting) dial pulses
or DTMF tones.
Figure 135
Ground start call states - incoming call from CO/FX/WATS
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 02.06 Standard
27 August 2008
Copyright © 2003-2008 Nortel Networks
.