Avaya Octel 200 Installation And Maintenance Manual page 903

ISDN Integration 16-1
16.1 ISDN INTEGRATION OVERVIEW
ISDN integration uses the DTIC card as the connection between the message server and the PBX. Each
DTIC card can have up to 30 ports authorized with capacity-on-demand.
This feature provides message-waiting indication and called-party identification. Refer to the Adaptive
Integration chapter for more general information about Adaptive Integration.
With ISDN integration, one digital pathway between the PBX and the Octel 200/300 message server
transmits both call information and voice communications. The pathway is provided by a 2 MB,
32-channel digital link from the PBX to the DTIC-E1 card. The first channel, time slot 0, is for
synchronization; channel 16 is the data channel that transmits the call information; and the other 30
channels are available for voice and fax transmission.
Using channel 16, which is referred to in ISDN terminology as the D-channel, call record information is
sent so that the message server has information about the source and destination of the call and the reason
for its arrival. The message server processes information from the data channel, answers the call and
plays the appropriate greeting. Message-waiting indication uses the D-channel in conjunction with a
voice channel. There is no requirement to designate channels or ports to perform MWI tasks.
As with other DSP-based cards, the DTIC processed the voice signal received from the PBX in digitized
form. The encoding algorithm used by ISDN switches is A-law, so it is important to ensure that the
message server is set up to be properly compatible.
As noted further in this chapter, the messages sent through the data channel are extensive and provide
much more information than is available with earlier integrations. Such integrations, based on the RS-232
SMDI protocol or on collecting call record data sent through DTMF tones or captured by emulating
telephones with LED displays, typically provide the type of call (direct or forwarded), the source (called
party identification if internal or trunk group if external), the destination (called party), and the reason for
the call (if forwarded). With this limited information, the typical configuration for integrated systems is
such that the caller who has entered digits to reach an extension is transferred, the PBX forwards that
caller back to a different port, and the transferring port hangs up. With the ISDN integration, the transfer
and forward back scenario no longer applies. For example, when a call extended through the ISDN switch
reaches a station that is busy, that condition is identified in the call record, the call remains on the
channel that answered originally, and the caller is prompted as would be expected based on the
configuration. In general, the mailbox holder class of service is not configured for transfer to ringing. If
not configured, the calling party will hear silence or music on hold until the call is connected.
PB60019-01 Octel 200/300 S.4.1