Matrix Visionpro System Manual page 60

So, Disconnect Supervision signal is important, particularly when calls are routed from CO-to-CO ports, to
indicate to the system that it needs to disconnect the call and release the port.
Disconnect Supervision signal has three options:
• None: When there this no signaling supported. Configure this option only if there is no Disconnect
Supervision signal supported.
• Polarity Reversal: Call disconnection is signaled as Polarity Reversal when the call is disconnected by
the remote user. For example, if the battery polarity of the CO port is '+ve' for TIP and '-ve' for RING in
speech condition then on disconnection by the remote user, TIP will become '-ve' and RING '+ve'. The
user gets an Error tone and the CO port is released.
• Open Loop Disconnect: Call Disconnection is signaled in the form of Open Loop, whereby the Battery
voltage on the CO port is removed for a short duration. Voltage is restored after this short duration.
However, the Polarity of Battery Voltage on the CO port is not changed.
This option is to be selected when call disconnection is signaled in the form of Open Loop Disconnect
pulse by the CO network. System will check Open Loop Disconnect signal for the time configured for
Open Loop Disconnect Timer for each CO port. If the time of the Open Loop signal detected is less
than the Open Loop Disconnect Timer configured, it will not be considered as valid Open Loop signal
for releasing the CO port. But if Open loop is detected continuously for at least for the time duration set
as the Open Loop Disconnect timer, it is considered as a valid Disconnect Supervision signal. The call
will be released and caller will get Error tone.
By default, Disconnect Supervision is set to None for each CO port.
Select the same Disconnect Supervision signal as provided by your CO Network.
Select the same Answer Supervision and Disconnect Supervision signal type supported by your CO
network for the CO ports. Consider the following case:
The CO network supports Polarity Reversal signal as Answer and Disconnect Supervision. But you have
configured 'Pseudo Answer' as Answer Supervision signal and 'Polarity Reversal' as Disconnect
Supervision signal for the CO ports in the system.
In this case, when a call is made through the CO port, the call will be considered as matured after the
Pseudo Answer Supervision Timer. Now, when the called party answers the call, the CO generates
'Polarity Reversal' as answer supervision signal on the CO port. But as 'Polarity Reversal' is also
configured as the Disconnect Supervision for the port, the system will interpret this (Answer Signaling)
signal as Disconnect Supervision signal and disconnect the call.
• Open Loop Disconnect Timer (ms): This parameter is applicable only if the option Open Loop
Disconnect is configured as the Disconnect Supervision type on the CO port.
The range of this timer is from 017 to 986 milliseconds. By default, the Timer is set to 204ms.
• Call Disconnect Tone Detection: This parameter is to be configured if Call Disconnection is signaled by
the CO network in the form of Disconnect Tone.
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