On Communication Manager, with the Extension to Cellular feature, extensions can be remotely connected over an ISDN trunk. Unlike traditional off-premises extensions, the stations are not tied to fixed channels on the T1/E1 interface. Instead, channels are allocated dynamically with each new call, providing significantly more efficient use of the T1/E1 interfaces through traffic engineering.
Routing of Extension to Cellular extended calls takes the following path:
ARS (or AAR) digit conversion is applied to the administered dial prefix and cell phone number.
ARS (or AAR) analysis is applied to the result of Step 1.
The ARS (or AAR) analysis selects a routing pattern.
Each entry in the routing pattern is tried in order. However, if the trunk group for a particular entry is non-ISDN or non-IP and not R2FMC, the trunk group is skipped.
A trunk group is chosen for the Extension to Cellular call and the call is sent.
If no trunk is available, the Extension to Cellular call is not extended. However, the original call is unaffected. The caller continues to hear ringback tone either until voice mail covers the call or the caller disconnects.
When the multiple locations customer option is enabled on Communication Manager, location-based routing tables are chosen as follows:
For calls sent to the cell phone the location used is:
The location administered on the off-pbx station-mapping form
The location of station
For calls dialed from the cell phone the location used is:
The location administered on the off-pbx station-mapping form
The location administered on the station form. Communication Manager uses the location of the incoming trunk if the location field on the station form is left blank.
