Synopsis
Waits for a specified amount of silence
Description
WaitForSilence(silencerequired[|iterations][|timeout])
Wait for Silence: Waits for up to ‘silencerequired’ milliseconds of silence, ‘iterations’ times or once if omitted.
An optional timeout specified the number of seconds to return after, even if we do not receive the specified amount of silence.
Use ‘timeout’ with caution, as it may defeat the purpose of this application, which is to wait indefinitely until silence is detected
on the line. This is particularly useful for reverse-911-type call broadcast applications where you need to wait for an answering
machine to complete its spiel before playing a message. The timeout parameter is specified only to avoid an infinite loop in
cases where silence is never achieved. Typically you will want to include two or more calls to WaitForSilence when dealing with an answering machine; first waiting for the spiel to finish, then waiting for the beep, etc.
Examples:
– WaitForSilence(500|2) will wait for 1/2 second of silence, twice
– WaitForSilence(1000) will wait for 1 second of silence, once
– WaitForSilence(300|3|10) will wait for 300ms silence, 3 times,
and returns after 10 sec, even if silence is not detected
Sets the channel variable WAITSTATUS with to one of these values:
SILENCE – if exited with silence detected
TIMEOUT – if exited without silence detected after timeout
Bugs
May 2008: We have noticed problems with the version of waitforsilence in Asterisk 1.2 and we use this version that was posted on the bug tracker a while ago: http://www.eflo.net/files/app_waitforsilence.c
See also
July 26, 2017
Phone System 