Nortel 1000 Fundamentals page 240

240 Appendix A Call Flow and protocol details
Figure 94
Inbound call to OC client with SPS, OC client answers
Incoming calls to OC 2007 can originate directly from a phone behind
the Communication Server 1000 where the request URI represents the
destination.
Incoming calls can also come from a PCA , where the Request URI is a
service DN used to route the call to OCS 2007, and the actual destination is
determined by a special header (x-nt-ocn) that contains the destination DN.
MCM checks for the x-nt-ocn and routes the call accordingly.
Personal Call Assistant (PCA) configuration provides additional Office
Communicator features such as forwarding to voice mail, and so on.
Configuration of PCA is performed through station administration tools.
This scenario as illustrated in
phone answers" (page 241)
on the network (instead of SPS).
For example, A Communication Server 1000 user dials 5555 which is the
phone belonging to user Bob in the demo.com domain. Bob accepts the call
from his phone (instead of the OC client).
Nortel Converged Office Fundamentals — Microsoft Office Communications Server 2007
Copyright © 2005–2008, Nortel Networks
.
Figure 95 "Inbound call to OC client with SRS,
depicts the presence of an SRS component
Nortel Communication Server 1000
NN43001-121 01.03 Standard
Release 5.0 30 April 2008