Asteroute Call Services are invoked by directing incoming calls to an Asteroute SIP URI (Universal Resource Indicator) having the form <Service>

 Where <Service> is the name given by the Asteroute user to identify a set of Call Routing Plans.

Each service may be assigned a time-zone, so that Call Routing Plan details and the call routing graph may be viewed in the appropriate time-zone.

Each service can have only one ACTIVE Call Routing Plan at any time.

A Call Routing Plan is a sequence of steps to define how an incoming call is managed.

A step may terminate the plan by playing a recorded announcement or directing the incoming call to a PSTN or SIP URI destination.

A step may invoke a Selector object that applies a predifined rule to select one option from one or more possible options.

Selector rules may be fixed (SWITCH), contextual (Time-of-Day), based on caller input (IVR type selectors) or may be used to provide a single complex funcion (record an announcement).

An ACTIVE Call Routing Plan cannot be changed, but the proporties of most Selectors may be changed in order to modify the way that incoming calls are managed. The IVR selectors IVROPT, IVRDATA and TTSOPT cannot be changed while the CRP is ACTIVE, because their options are fixed to the structure of the CRP.