3Com VCX v7111 User Manual page 259

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 – see Adding a Reorder Tone to the
CPT File). This method is slightly less reliable than the previous one. You can use the
CPTWizard (described in Creating a Loadable Prerecorded Tones File) to analyze Call
Progress Tones generated by any PBX or telephone network.
Relevant parameters: DisconnectOnBusyTone and DisconnectOnDialTone.
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
(with DSP templates number 2 or 3).
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.
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3Com VCX V7111 VoIP Gateway User Guide