Considerations for the Call Vectoring Features

It is perfectly acceptable for a vector to route a call over an ISDN-PRI facility to a destination that is not a VDN. In such a case, the sending switch treats the call like a Look-Ahead Interflow call. Generic ISDN processing at the receiving switch causes the call to be accepted. The DNIS name is ignored.

If a Look-Ahead Interflow call terminates to a VDN on a receiving switch where the Look-Ahead Interflow option is not enabled, intelligent interflow still results. However, any relevant DNIS information is ignored, and intelligent interflow to far-end switches is not possible.

The LAI timeout in the sending switch occurs after two minutes.

T-1 equipment might modify the ISDN D-channel that is used for Look- Ahead Interflow. If multiplexors are introduced into the ISDN-PRI circuit, bit compression and echo cancellation must be turned off for the D- channel.

Adjunct Routing Considerations

The following are considerations you should keep in mind when working with Adjunct Routing:

Depending upon your application, you may want to include a second adjunct routing step in your vector in case the first such step fails.

If you include an announcement step immediately after an adjunct routing step, be sure the announcement does not contain any information essential to the caller (such as further instructions) since the step following the adjunct routing step immediately terminates the moment the switch receives a destination from the ASAI adjunct.

If you include a wait-timestep after an adjunct routing step, it is a good idea to specify either ringback or music (and not silence) as the feedback. If the caller does not hear any feedback, he or she might give up on the call and hang up.

The second step after the adjunct routing step could (and, in many cases, should) be implemented as a default treatment in case the host application or ASAI link is down. The step containing this default treatment (for example, route-to number 0 if unconditionally) executes immediately if the ASAI link is down and if the step is preceded by either a wait-timeor an announcement step. On the other hand, if the host application is down, the default step executes only if the application does not respond with a route within 20 seconds.

C-4Issue 4 September 1995

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AT&T 555-230-520 manual Adjunct Routing Considerations