Linksys SPA 900 Benutzerhandbuch

A client station is a Linksys IP phone with one or more extensions and call appearances provisioned An 
extension in the Linksys IP 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 Linksys IP 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. Linksys IP phones include a rich set of configurationx 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: 

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) 

A Call State is the Call Appearance State applied to a specific call instance. Call States are divided into 
two general categories:

Active (Call) State: If the state is Dialing, Calling, Proceeding, Connected, or Invalid. When the 
state of the Call is Active, it is referred to as an Active Call 

Standby (Call) State: the state is Ringing or Holding. When the state of the Call is Standby, it is 
referred to as a Standby Call