Nortel Networks 9150 - Manual (Page 68)

38 Remote Gateway 9150 Installation and Administration Guide
Remote Gateway 9150 description Standard 3.1
The Remote Gateway 9150 unit discovers the DN numbers of the local digital
telephones either through DN Discovery or configuration. The Bridge Ports,
Local Calling, and Local SwitchOver features depend on this knowledge as
follows:
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If a call has an appearance on a Local Calling key, the Remote Gateway
9150 unit first attempts to complete the operation (for example, call,
transfer, forward) using the local dialing plan.
!
If a call is placed from a Local Calling key to a number not found in the
Remote Gateway 9150 unit’s local list, then a Bridge Port is used to place
the intended call to the host PBX.
Local extension calling
When you place a call to another telephone in your office using the local call
appearance key, it is handled by the Remote Gateway 9150 unit, not the host
PBX.
Note: If the call is initiated from the host call appearance key, then the
station-to-station call requires transmission of signaling data through the host
PBX.
Local SwitchOver
Local SwitchOver is a mechanism that the Remote Gateway 9150 unit uses to
determine if a PBX-controlled call that originated on the Remote Gateway 9150
unit is destined for a DN on the same Remote Gateway 9100 Series unit.
Note: The DN Discovery feature is necessary for the Local SwitchOver feature
to work properly. Refer to the Reach Line Card Installation and Administration
Guide (NTP 555-8421-210) for more information.
In this situation, the Remote Gateway 9150 unit switches to a local 64K channel
and cross-connect the voice-paths of the phone without using wide area
bandwidth.
There are times, however, when the Remote Gateway 9150 unit does not know
that an incoming and outgoing call are part of the same call (for example, you
transfer/forward a call within the same PBX, or re-dial the last number).
Although the call still functions, it consumes Wide Area bandwidth.
Local SwitchOver is not available if the call is answered with the Handsfree
button on M39xx telephones.