Answer and Disconnect Supervision Parameters

The answer and disconnect supervision parameters are described in the table below.

Answer and Disconnect Parameters

Parameter

Description

'Wait before PSTN Release-Ack'

configure voip > gateway digital settings > wait-befor-pstn-rel-ack

[TimeToWaitForPstnReleaseAck]

Defines a timeout (in milliseconds) that the device waits for the receipt of an ISDN Q.931 Release message from the PSTN side before releasing the channel. The Release ACK is typically sent by the PSTN in response to the device's Disconnect message to end the call. If the timeout expires and a Release message has not yet been received, the device releases the call channel.

The valid value is 1 to 360,000. The default is 6,000.

Note: The parameter is applicable only to digital interfaces.

configure voip > interface e1-t1 > isdn-japan-ntt-timer-t305

[ISDNJapanNttTimerT305]

Defines a timeout (in seconds) that the device waits before sending an ISDN Release message after it has sent a Disconnect message, if no SIP message (e.g., 4xx response) is received within the timeout. The parameter is applicable when the device's trunk is configured for the Japanese NTT ISDN PRI (T1) variant (i.e., [ProtocolType] is [16], as described in Configuring Trunk Settings).

The valid value is 0 to 480. The default is 0 (i.e., timeout is 30 seconds).

For more information on this feature, see SIP-to-ISDN Disconnect Release Cause Code Mapping.

Note:

For the parameter to take effect, a device restart is required.
The parameter is applicable only to digital interfaces (T1 NTT).

'Answer Supervision'

configure voip > gateway analog fxo-setting > answer-supervision

[EnableVoiceDetection]

Enables the sending of SIP 200 OK upon detection of speech, fax, or modem.

[1] Yes = The device sends a SIP 200 OK (in response to an INVITE message) when speech, fax, or modem is detected (from the Tel side, for analog interfaces).
[0] No = (Default) The device sends a SIP 200 OK only after it completes dialing (to the Tel side, for analog interfaces).

Typically, this feature is used only when early media, enabled by the [EnableEarlyMedia] parameter, is used to establish the voice path before the call is answered.

Note:

The parameter is applicable only to the Gateway application.
FXO interfaces: The feature is applicable only to one-stage dialing (FXO).
Digital interfaces:
The parameter is applicable only when the protocol type is CAS.
To activate the feature, configure the [EnableDSPIPMDetectors] parameter to 1.

'GW Max Call Duration'

configure voip > sip-definition settings > gw-mx-call-duration

[GWMaxCallDuration]

Defines the maximum duration (in minutes) per Gateway call. If this duration is reached, the device ends the call. This feature is useful for ensuring that device resources are available for new calls.

The valid range is 0 to 35,791. A value of 0 means unlimited duration. The default is 0.

Note: The parameter is applicable only to the Gateway application.

configure voip > sip-definition settings > mn-call-duration

[MinCallDuration]

Defines the minimum call duration (in seconds) for the Tel side. If an established call is terminated by the IP side before this duration expires, the device terminates the call with the IP side, but delays the termination toward the Tel side until this timeout expires.

The valid value range is 0 to 10 seconds, where 0 (default) disables this feature.

For example: assume the minimum call duration is set to 10 seconds and an IP phone hangs up a call established with a BRI phone after 2 seconds. As the call duration is less than the minimum call duration, the device doesn't disconnect the call on the Tel side. However, it sends a SIP 200 OK immediately upon receipt of the BYE to disconnect from the IP phone. The call is disconnected from the Tel side only when the call duration is greater than or equal to the minimum call duration.

Note:

The parameter is applicable only to the Gateway application.
The parameter is applicable to IP-to-Tel and Tel-to-IP calls.
The parameter is applicable only to ISDN and CAS protocols.

'Disconnect on Dial Tone'

configure voip > gateway analog fxo-setting > disc-on-dial-tone

[DisconnectOnDialTone]

Determines whether the device disconnects a call when a dial tone is detected from the PBX.

[0] Disable = (Default) Call is not released.
[1] Enable = Call is released if a dial tone is detected on the device's FXO port.

Note:

The parameter is applicable only to FXO interfaces.
This option is in addition to the mechanism that disconnects a call when either busy or reorder tones are detected.

'Send Digit Pattern on Connect'

configure voip > sip-definition settings > digit-pttrn-on-conn

[TelConnectCode]

Defines a digit pattern to send to the Tel side after a SIP 200 OK is received from the IP side. The digit pattern is a user-defined DTMF sequence that is used to indicate an answer signal (e.g., for billing).

The valid value is up to 8 characters.

Note: The parameter is applicable only to FXO and CAS.

'Broken Connection Mode'

configure voip > sip-definition settings > disc-broken-conn

[DisconnectOnBrokenConnection]

Global parameter that defines the device's handling of calls if RTP or MSRP packets are not received within a user-defined timeout (configured by the 'Broken Connection Timeout' parameter) during an established call (i.e., packet flow suddenly stops during the call).

You can also configure this feature per specific calls, using IP Profiles ('Broken Connection Mode'). For a detailed description of the global parameter and for configuring this feature in the IP Profiles table, see Configuring IP Profiles.

Note: If you configure this feature for a specific IP Profile, the device ignores this global parameter for calls associated with the IP Profile.

'No RTP Mode'

configure voip > sbc settings > no-rtp-mode

[NoRTPMode]

Global parameter that defines the device's handling of calls if RTP packets are not received (detected) during early media or upon call connect (i.e., never was RTP) within a timeout. The timeout is configured by the [NoRTPDetectionTimeout] parameter.

You can also configure this feature per specific calls, using IP Profiles ('No RTP Mode' parameter). For a detailed description of the global parameter and for configuring this feature in the IP Profiles table, see Configuring IP Profiles.

Note:

If you configure this feature for a specific IP Profile, the device ignores this global parameter for calls associated with the IP Profile.
The parameter is applicable only to the SBC application.

'Broken Connection Timeout'

configure voip > sip-definition settings > broken-connection-event-timeout

[BrokenConnectionEventTimeout]

Defines the timeout interval (in 100-msec units) after which a call is disconnected if RTP packets are not received during an established call (i.e., packet flow suddenly stops during the call).

The valid range is from 3 (i.e., 3 x 100 = 300 msec) to approx. 2684354 (i.e., 74.5 hours). The default is 100 msec.

Note:

The parameter is applicable only when the 'Broken Connection Mode' parameter is configured to Disconnect.
For this feature to function, you also need to disable silence suppression.

configure voip > sbc settings > no-rtp-detection-timeout

[NoRTPDetectionTimeout]

Defines the timeout interval (in msec) after which a call is disconnected or re-routed if RTP packets are not received within the interval.

The valid range is 0 to 50000. The default is 0, which means that this timeout feature is disabled and that the device doesn't disconnect the call due to packets not being received.

Note:

The parameter is applicable to the 'Broken Connection Mode' and 'No RTP Mode' parameters.
If a call is already established and RTP exists and at any stage during the call packets are not detected for a user-defined interval (configured by the 'Broken Connection Timeout' parameter), the device disconnects the call or routes it to an alternative destination, configured by the IP Profile parameter 'Broken Connection Mode'.
The parameter is not applicable to MSRP and direct media calls for the SBC application (see Direct Media Calls).

'Timeout to Establish MSRP Connection'

configure voip > sbc settings > msrp-connection-establish-timeout

[MSRPConnectionEstablishTimeout]

Defines the timeout (msec) for establishing MSRP connections.

The timer starts from when the device opens the MSRP media socket (port). If the timeout expires and the connection wasn't established, the device does one of the following:

Ends the SIP session.
If you've enabled the Broken Connection feature, the device searches for an alternative route in the IP-to-IP Routing table. For more information, see the IP Profile's 'Broken Connection Mode' parameter in Configuring IP Profiles.

The valid value is 10000 to 120000. The default is 10000 (i.e., 10 sec).

For more information, see Configuring Message Session Relay Protocol.

'Trunk Alarm Call Disconnect Timeout'

trk-alrm-call-disc-to

[TrunkAlarmCallDisconnectTimeout]

Defines the duration (in seconds) to wait after a digital trunk Red alarm (LOS / LOF) is raised, before the device disconnects the SIP call. If this timeout expires and the alarm is still raised, the device sends a SIP BYE message to terminate the call. If the alarm is cleared before this timeout expires, the call is not terminated, but continues as normal.

The range is 1 to 3600. The default is 0 (20 for BRI, 20 for E1 and 40 for T1).

Note: The parameter is applicable only to the Gateway application.

'Disconnect Call on Busy Tone Detection (ISDN)'

configure voip > gateway digital settings > disc-on-bsy-tone-i

[ISDNDisconnectOnBusyTone]

Determines whether a call is disconnected upon detection of a busy tone (for ISDN).

[0] Disable = (Default) Do not disconnect call upon detection of busy tone.
[1] Enable = Disconnect call upon detection of busy tone.

Note:

The parameter is applicable only to ISDN protocols.
IP-to-ISDN calls are disconnected on detection of SIT tones only in call alert state. If the call is in connected state, the SIT doesn't disconnect the calls. Detection of busy or reorder tones disconnects the IP-to-ISDN calls also in call connected state.
For IP-to-CAS calls, detection of busy, reorder, or SIT tones disconnect the calls in any call state.

'Disconnect Call on Busy Tone Detection (CAS)'

configure voip > gateway analog fxo-setting > disc-on-bsy-tone-c

[DisconnectOnBusyTone]

Global parameter enabling call disconnection upon detection of a busy tone.

You can also configure the feature per specific calls, using Tel Profiles ('Disconnect Call on Detection of Busy Tone' parameter). For a detailed description of the parameter and for configuring the feature in the Tel Profiles table, see Configuring Tel Profiles.

Note:

The parameter is applicable only to the Gateway application.
If the feature is configured for a specific Tel Profile, the settings of the global parameter is ignored for calls associated with the Tel Profile.

Polarity (Current) Reversal for Call Release (Analog Interfaces) Parameters

configure voip > interface fxs-fxo > default-linepolarity-state

[SetDefaultLinePolarityState]

Defines the FXO line polarity, required for DID signaling.

[0] = Positive line polarity
[1] = Negative line polarity
[2] = (Default) Auto - The device detects the polarity upon power-up or upon insertion of the RJ-11 cable, and uses it as a reference polarity.

Typically, if the RJ-11 cabling is connected correctly (without crossing, Tip to Tip, Ring to Ring), the Tip line is positive compared to the Ring line. In this case, set the parameter to 0. With this configuration, the device assumes that the idle line polarity is Tip line positive.

When the device receives a SIP INVITE, it checks the FXO line polarity. If the polarity is "Reversed", it skips this FXO line and goes to the next line.

Note:

For the parameter to take effect, a device restart is required.
To take advantage of this new feature, configure all FXO lines as a single Trunk Group with ascending or descending channel select mode, and configure routing rules to route incoming INVITE messages to this Trunk Group.
The parameter is applicable only to FXO interfaces.

'Enable Polarity Reversal'

configure voip > sip-definition settings > polarity-rvrsl

[EnableReversalPolarity]

Global parameter enabling the Line Polarity Reversal feature for call release.

You can also configure the feature per specific calls, using Tel Profiles ('Enable Polarity Reversal' parameter). For a detailed description of the parameter and for configuring the feature in the Tel Profiles table, see Configuring Tel Profiles.

Note:

The parameter is applicable to FXS and FXO interfaces.
If the feature is configured for a specific Tel Profile, the settings of the global parameter is ignored for calls associated with the Tel Profile.

'Enable Current Disconnect'

configure voip > sip-definition settings > current-disc

[EnableCurrentDisconnect]

Global parameter enabling call release upon detection of a Current Disconnect signal.

You can also configure the feature per specific calls, using Tel Profiles ('Enable Current Disconnect' parameter). For a detailed description of the parameter and for configuring the feature in the Tel Profiles table, see Configuring Tel Profiles.

Note:

The parameter is applicable to FXS and FXO interfaces.
If the feature is configured for a specific Tel Profile, the settings of the global parameter is ignored for calls associated with the Tel Profile.

configure voip > interface fxs-fxo > polarity-reversal-type

[PolarityReversalType]

Defines the voltage change slope during polarity reversal or wink.

[0] = (Default) Soft reverse polarity.
[1] = Hard reverse polarity.

Note:

The parameter is applicable only to FXS interfaces.
Some Caller ID signals use reversal polarity or Wink signals, or both. In these cases, it is recommended to configure the parameter to [1] (Hard).
For the parameter to take effect, a device restart is required.

configure voip > interface fxs-fxo > current-disconnect-duration

[CurrentDisconnectDuration]

Defines the duration (in msec) of the current disconnect pulse.

The range is 200 to 1500. The default is 900.

Note:

The parameter is applicable for FXS and FXO interfaces.
The FXO interface detection window is 100 msec below the parameter's value and 350 msec above the parameter's value. For example, if the parameter is set to 400 msec, then the detection window is 300 to 750 msec.
For the parameter to take effect, a device restart is required.

[CurrentDisconnectDefaultThreshold]

Defines the line voltage threshold at which a current disconnect detection is considered.

The valid range is 0 to 20 Volts. The default is 4 Volts.
Note:

The parameter is applicable only to FXO interfaces.
For the parameter to take effect, a device restart is required.

configure voip > interface fxs-fxo > time-to-sample-analog-line-voltage

[TimeToSampleAnalogLineVoltage]

Defines the frequency at which the analog line voltage is sampled (after offhook), for detection of the current disconnect threshold.

The valid range is 100 to 2500 msec. The default is 1000 msec.

Note:

The parameter is applicable only to FXO interfaces.
For the parameter to take effect, a device restart is required.