User`s manual

SIP User's Manual 8. Telephony Capabilities
Version 5.0 225 December 2006
Two-stage dialing implements the Dialing Time feature. Dialing Time allows you to define
the time that each digit can be separately dialed. By default, the overall dialing time per
digit is 200 msec. The longer the telephone number, the greater the dialing time will be.
The relevant parameters for configuring Dialing Time include the following:
 DTMFDigitLength (100 msec): time for generating DTMF tones to the PSTN (PBX)
side
 DTMFInterDigitInterval (100 msec): time between generated DTMF digits to PSTN
(PBX) side
8.4.1.3 Call Termination (Disconnect Supervision) on the FXO Gateway
The FXO Disconnect Supervision enables the gateway's FXO ports to monitor call-
progress tones from a PBX or from the PSTN. This allows the FXO to determine when the
call has terminated on the PBX side, and thereby, preventing analog trunks (i.e., lines to
the PBX) from getting “stuck” when the called phone hangs up.
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 -- refer to Section E.2.7 on
page 374). This method is slightly less reliable than the previous one. You can use the
CPTWizard (described in Section E.1.3 on page 366) 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.