Administrator's Guide

Features and technical reference
555-233-5061898 Issue 5 October 2002
Interactions
■ DCS Trunk Turnaround
OTTOTT increases the set of cases in which DCS Trunk Turnaround may
be accepted. However, use of OTTOTT in combination with a DCS
network is strongly discouraged. The following algorithm describes the
DCS Trunk Turnaround request process.
a. If any party on the call receives a local-dial, busy, intercept, or
reorder tone, deny turnaround.
b. If any remaining party is an answered station or attendant, accept
turnaround.
c. If any remaining party is on an incoming trunk, accept turnaround.
For the purposes of this check, an outgoing DCS trunk that has been
turned around an odd number of times via a DCS trunk turnaround
is considered an incoming trunk with disconnect supervision.
Similarly, an incoming DCS trunk that has been turned around an
odd number of times is considered an outgoing trunk.
d. If any remaining party is an outgoing trunk administered for
OTTOTT that has received answer supervision, accept turnaround.
e. If any remaining party is an outgoing DCS trunk, forward the
turnaround request.
f. Otherwise, deny turnaround.
■ Incoming Disconnect Supervision
Outside of the U.S., incoming disconnect supervision is a switch capability
that restricts transfers or conferences for certain incoming trunks. In the
U.S., all incoming trunks are assumed to provide disconnect supervision. In
some countries this assumption is not valid, so administer whether or not
an incoming trunk provides disconnect supervision for each trunk group.
■ Personal Central Office Lines (PCOLs)
Transfer of PCOLs is not subject to the normal restrictions applied to
transfer of other trunks. These transfers are allowed since the PCOL
appearance remains on one or more stations as a feature button. System
users must be aware that the DROP button cannot be used to disconnect the
transferred-to party from the call. Hence, if an outgoing PCOL is
transferred to an outgoing trunk and neither of the trunks can supply a
disconnect signal, the two trunks lock up.
■ QSIG Global Networking
If either call is over an ISDN-PRI trunk administered with Supplementary
Service Protocol b (QSIG), additional call information may display.