Call Termination On Fxo Devices; Calls Termination By Pbx - AudioCodes MP-124 User Manual

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FXO sends a hook-flash to the PBX, dials the digits (that are received in the
Refer-To header), and then drops the line (on-hook). Note that the time between
flash to dial is according to the WaitForDialTime parameter.
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PBX performs the transfer internally
Hold / Transfer toward the IP side: The FXO device doesn't initiate hold / transfer as
a response to input from the Tel side. If the FXO receives a REFER request (with or
without replaces), it generates a new INVITE according to the Refer-To header.
9.6.3

Call Termination on FXO Devices

This section describes the device's call termination capabilities for its FXO interfaces:
Calls terminated by a PBX (refer to ''Call Termination by PBX'' on page 410)
Calls terminated before call establishment (refer to ''Call Termination before Call
Establishment'' on page 411)
Ring detection timeout (refer to ''Ring Detection Timeout'' on page 411)
9.6.3.1

Calls Termination by PBX

The FXO device supports various methods for identifying when a call has been terminated
by the PBX.
The PBX doesn't disconnect calls, but instead signals to the device that the call has been
disconnected using one of the following methods:
Detection of polarity reversal/current disconnect: The call is immediately
disconnected after polarity reversal or current disconnect is detected on the Tel side
(assuming the PBX/CO generates this signal). This is the recommended method.
Relevant parameters: EnableReversalPolarity, EnableCurrentDisconnect,
CurrentDisconnectDuration, CurrentDisconnectDefaultThreshold, and
TimeToSampleAnalogLineVoltage.
Detection of Reorder, Busy, Dial, and Special Information Tone (SIT) tones: The
call is immediately disconnected after a Reorder, Busy, Dial, or SIT 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 not known, define them in the CPT file (the tone produced by
the PBX / CO must be recorded and its frequencies analyzed -- refer to Adding a
Reorder Tone to the CPT File in the Reference Manual). This method is slightly less
reliable than the previous one. You can use the CPTWizard (described in the
Reference Manual) 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 option.
Relevant parameters: EnableSilenceDisconnect and FarEndDisconnectSilencePeriod.
Special DTMF code: A digit pattern that when received from the Tel side, indicates to
the device to disconnect the call.
Relevant ini file parameter: TelDisconnectCode.
SIP User's Manual 410
MP-11x & MP-124
Document #: LTRT-65412