EMEA IP Office Technical Tip

045: Analogue Trunk Disconnect Clear Operation

19th July 2004 - Full PDF Text Version

 

The IP Office uses two methods to disconnect Analogue calls :-

  1. Line Break Disconnect (also known as Reliable Disconnect)
    Detection of a Line Break condition (defined as < 5mA loop current in the line) for a period greater than that set by the Disconnect Clear Timer.

or

  1. Tone Disconnect
    Detection of a continuous Busy, or NU Tone, for 6 seconds.

 

Currently the Line Break Disconnect is only available for USA, Canada and UK, all other countries use Tone Disconnect.

When the Analogue Trunk -> Disconnect Clear checkbox is Selected the IP Office will disconnect a call whenever it detects a Line Break condition on the Trunk for a time greater than that set in the Analogue Trunk -> Disconnect Clear Timer box ( + 120mS) - i.e. the IP Office expects a Line Break Disconnect event on this Trunk and NOT a NU/Busy Tone Disconnect.

When the Analogue Trunk -> Disconnect Clear checkbox is Not Selected the IP Office will only disconnect a call on that Analogue Trunk when it detects a 6 second continuous NU/Busy Tone - i.e. it never tries to detect a Line Break Disconnect event.

For those countries that use Tone Disconnect to clear a call (i.e. all countries except USA, Canada and the UK) the IP Office sends special information on initial call setup/connect when an incoming call from an Analogue Trunk is routed to the Voicemail Server/Auto Attendant. If this call results in any form of Voicemail Recording/Message the Voicemail Server/Auto Attendant uses the special call setup/connect information to delete the last six seconds of any Recording/Message that is left (otherwise the Recording/Message would contain the 6 seconds of Busy/NU Tone that is required to detect the Disconnection).

When the Analogue Trunk -> Disconnect Clear checkbox is Selected on a Trunk that does NOT provide a Line Break Disconnect event the IP Office will still disconnect a call when it detects a 6 second continuous NU/Busy Tone - i.e. the IP Office will disconnect this Trunk whenever a Line Break Disconnect OR a NU/Busy Tone Disconnect event is detected.

 

Note :-