Waiting a Minimum Number of Rings
function can be used by any application to determine the number of times an
inbound call on the given address should ring before the call is to be answered.
Waiting a certain number of rings allows callers to be spared the charge of a
call connection if it seems that the call will not be answered by the desired
party (usually a person). This feature is sometimes called toll-saver
support. Applications can use the functions lineGetNumRings
in combination to provide a mechanism to support toll-saver features for
multiple independent applications.
Any application that receives a handle for a call in the offering state and a LINE_LINEDEVSTATE
ringing message should wait a number of rings equal to the number returned by lineGetNumRings
before answering the call in order to honor the toll-saver settings across
all applications. The function lineGetNumRings
returns the minimum number of rings any application has specified with the
. Because this number may vary dynamically, an application should call lineGetNumRings
each time it has the option to answer a call
that is, when it is the owner of a call still in the offering
state. A separate LINE_LINEDEVSTATE ringing message is sent to the
application for each ring cycle.
If the service provider is set to auto-answer calls, it answers after a
certain number of rings. Service providers do not have access to the minimum-ring
information established by lineSetNumRings
, and therefore will make their own determination of when to automatically
answer an incoming call. When a call has been so answered by a service provider,
it will be initially delivered to the owning application already in the connected
state, so the application will not need to be concerned with counting rings
or with answering the call.
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