MP114/118: Add new tones to the CPT file
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How to terminate a call on AudioCodes MP114/118 FXO gateways
The PBX doesn't disconnect the call, but instead signals to the gateway that the call is disconnected using one of the following methods:
- Detection of polarity reversal / current disconnect
This is the recommended method. The call is immediately disconnected after polarity reversal or current disconnect is detected on the Tel side (assuming the PBX / CO produces this signal). Relevant parameters: EnableReversalPolarity, EnableCurrentDisconnect, CurrentDisconnectDuration, CurrentDisconnectDefaultThreshold, and TimeToSampleAnalogLineVoltage.
- Detection of Reorder / Busy / Dial tones
The call is immediately disconnected after Reorder / Busy / Dial tone is detected on the Tel side (assuming the PBX / CO generates this tone). This method requires the correct tone frequencies and cadence to be defined in the Call Progress Tones file. If these frequencies are unknown, define them in the CPT file (the tone produced by the PBX / CO must be recorded and its frequencies analyzed). This method is slightly less reliable than the previous one. Relevant parameters: DisconnectOnBusyTone and DisconnectOnDialTone.
- A special DTMF code
A digit pattern that when received from the Tel side, indicates to the gateway to disconnect the call. Relevant ini file parameter: TelDisconnectCode.
- Detection of silence
The call is disconnected after silence is detected on both call directions for a specific (configurable) amount of time. The call isn’t disconnected immediately; therefore, this method should only be used as a backup mode. Relevant parameters: EnableSilenceDisconnect and FarEndDisconnectSilencePeriod.
To add a Reorder tone to the CPT file, take these steps
- Make a call (using G.711) between the MP FXO, which is connected to the PBX, and a remote entity in the IP network.
- Capture the call using a "network sniffer" such as Wireshark.
- Disconnect the call from the PBX side, and then wait approximately 30 seconds before stopping the Wireshark recording.
- In the network trace, locate the RTP stream sent from the FXO.
- Save the RTP payload on your PC as a *.pcm file by clicking Save Payload (Statistics menu > RTP > Stream Analysis. (Note: ensure that you select the ‘forward’ option.)
- Open the *.pcm file in a voice recording utility such as CoolEdit.
- Locate the tone that the PBX played to indicate the disconnected call (if such a tone exists).
- Locate the attributes of the tone -- its frequency and interval (on / off time).
- In the Call Progress Tones file, add a new Reorder Tone with the attributes you found in the previous step. Ensure that you update the numbers of the successive tones and the total number of tones in the beginning of the file.
- Create a Call Progress Tones.dat file using the DConvert Utility.
- Load the new file to the gateway, and then reset the gateway.