Medias Mediatrix 1204, Reference Manual

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Chapter 14 - Gateway Configuration Detecting a Far End Disconnect
190 Mediatrix 1204
Mediatrix 1204 Configuration
If you cannot activate the Current Drop/Power Denial Mode, set the Mediatrix 1204 to detect a far end
disconnect, which involves three separate parts:
Forcing the end of a call when the call has not been established.
Forcing the end of an existing call when silence is detected.
Forcing the end of an existing call when the far end tone is detected.
Forced End of Call on Unreachable Destination
The forced end of call occurs when a SCN caller tries to reach someone on the IP network and the SCN caller
hangs up before reaching the IP callee.
If the connection is not established, the Mediatrix 1204 cannot detect that the caller has hung up. You can
configure the Mediatrix 1204 to disconnect an unsuccessful communication after a specific number of
seconds. This number of seconds is defined in a timeout that starts to count when the SCN caller contacts the
Mediatrix 1204. If the connection is not successful, the line is closed when the call time reaches the defined
timeout value.
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To force the end of an unsuccessful call:
1. In the fxoMIB , set the fxoFeocOnCallFailureEnable variable to enable .
When the line falls into an error state where a SIT (Special Information Tone), a ROH (Receiver Off-
Hook), a Busy or any error tone is played, the Mediatrix 1204 waits for the timeout specified in
fxoFeocOnCallFailureTimeout and then hangs up.
2. Set the timeout after which to release the FXO line in the fxoFeocOnCallFailureTimeout variable.
Available values range between 0 and 180 seconds. The default value is 30 .
Forced End of Call on Silence Detection
The silence detection feature applies when two parties are in communication and one of them hangs up. It
allows the Mediatrix 1204 to close a line when no voice activity or silence is detected for a specified amount
of time.
When silence is detected on the IP and/or SCN side for an amount of time specified in a timeout, the call is
terminated. This feature is useful to free resources in the event of an IP network failure that prevents the end
of call to be detected or when the SCN end of call tone was not detected.
The current implementation of silence detection relies on the Voice Activity Detection (VAD) and Silence
Suppression features of the encoder used for the voice call. Silence is not processed the same way depending
on the codec used. This means that if you choose an encoder without VAD (silence suppression) – such as
G.711 without VAD, G.726 without VAD, G.729A without Annex B, or G.723.1 without Annex A – you cannot
detect silence at the end of a call.
Furthermore, the VAD of the encoder, when used, is adaptive. Mediatrix cannot guarantee the silence
detection at the end of call will work on all SCN/PBX lines. The level and type of noise when the SCN/PBX
terminates the call might prevent silence detection to work. Also, the voice level before the end of a call could
impact the way silence is detected.
Note:
If an FXO line is locked because of the far end disconnect problem, set the ifAdminSetAdmin variable
corresponding to the line to forcelock , then set it to unlock . This will restart the line without affecting the
other lines. See “Chapter 15 - Lines Administrative State” on page 195 for more details.
Note:
The silence detection feature could inadvertently disconnect a communication when one party puts
the other on hold.