Avaya Nortel Communication Server 1000 Reference page 386

NT8D14 Universal Trunk card
Incoming calls
The alerting signal into the System is 20 Hz (nominal) ringing sent by the CO. When an
incoming call is answered, ringing is tripped when the System places a low-resistance dc loop
across the tip and ring leads toward the CO. See
call from CO/FX/WATS
incoming call from CO/FX/WATS
Figure 105: Loop start call states - incoming call from CO/FX/WATS
386 Circuit Card Reference
on page 386 and Figure 106: Loop start call connection sequence -
on page 387.
Comments? infodev@avaya.com
Figure 105: Loop start call states - incoming
July 2011