Call Appearances And Extensions - Linksys 900 Series Administrator's Manual

Chapter 3 Managing Linksys 900 Series IP Phones

Call Appearances and Extensions

A client station is a SPA900 Series phone with one or more extensions and call appearances
provisioned An extension in the SPA900 Series phone is a VoIP account in an ITSP network or
an IP-PBX system. An extension can be identified with a unique user ID (typically, a phone
number).
Up to four extensions can be configured on a SPA922 or 942 Series phone, while up to six
extensions can be configured on a SPA962 phone. These are referred to as Ext n, or En, where
n is the numeric identifier of the extension, such as Ext 1 or E1.
When the same extension is configured on more than one station, it is called a shared extension.
Extension 1 is referred to as the primary extension. Some features can be activated only on the
primary extension, such as Call Forwarding and Voice Mail Waiting Indicator (VMWI).
A call appearance physically corresponds to a line key on a station. There are four line keys on
the SPA922 and 942 Series phones, and six line keys on the SPA962 phone. These are referred
to as Line Key n, or Ln, where n is the numeric identifier of the extension, such as Line 1 or
L1. Functionally, a call appearance is an instance of an extension. If an extension is assigned
to line keys on multiple stations, it is called a shared line appearance.
One extension can be assigned to multiple line keys on a SPA900 Series phone. In fact, all four
call appearances can be instances of the same extension. An extension is not a Shared Line
Appearance unless it is also assigned to a line key on another station. Any of the four line keys
can be disabled. Each call appearance supports one call at a time, either active or on hold.
The VoIP Interface (VI) refers to an extension and its associated control parameters that are
configured on a particular station. SPA900 Series phones include a rich set of configuration
parameters to control the operation of the phone. Configuring an extension includes
configuring the core account information and VI control parameters.
Although the account information is usually the same for a shared extension on different
stations, the rest of the VI parameters can differ. For example, the dial plan or the preferred
codec to use when making a call on this extension could be different for two different stations
sharing the extension.
A Call Appearance State refers to the state of a call appearance, which can be one of the
following:
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Disabled: The line key is disabled
Idle (Ready): The Call Appearance is ready for use
Dialing: Collecting digits from the user to be dialed out from this Line
Calling: Waiting for the called party to respond
Proceeding (a.k.a. Progressing): Called party station is ringing
Ringing (a.k.a. Alerting): Incoming call, station is ringing
Connected: Connected with remote party
Held: Remote party is on hold
Invalid: Remote party hangs up or error while attempting outbound call
Busy: the line is being used by another station (shared line only)
Call Appearances and Extensions
Linksys 900 Series IP Phone Administrator Guide
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