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Blind Hookflash

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Hi Support,


We have a new server (vgEngine : 7.5.6117.35767 RELEASE options75) which we are using to replace an existing automated attendant. The application is quite straight forward, caller dials in, selects from a DTMF menu and is transferred (with blind hookflash) to a 4 digit extension.


We have tried to replicate the existing system including hookflash timing, however the calls are hanging up when the transfer is attempted. We know transfers work on the analogue extensions as the existing system works (and is setup with 125 ms hookflash), and understand hangup likely indicates the hookflash was too long. However we have been reducing the hookflash and the call continues to hang up.


We thought the system would go off hook with a ! character and then the timing was controlled by the Transfer_Prefix_PauseAfter. However changing this setting, and restarting VG seems to make no difference, we have even set Transfer_Prefix_PauseAfter to 0 and expected to hear dialling of digits on the phone, but the call still hangs up. We also tried changing the transfer to monitored without any difference.


I have attached various logs of our testing and the VG.ini file.


Can you please suggest how to proceed or if we have misunderstood how to change hookflash timings.





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In VoiceGuide v7 the hookflash length is set in Config.xml file, using setting DXBD_FLASHTM


From http://www.voiceguide.com/vghelp/source/html/config_calltransfers.htm :

When using VoiceGuide for Dialogic the hookflash length is set in Config.xml file, in the Parmeters_DxBd section. The following section of Config.xml should be edited:

  <Description>Flash time during dialing (10ms units)</Description>

A setting of 10 means 100ms. The setting is in 10ms units.

From posted log files we can see that on your system the DXBD_FLASHTM is currently set to a value of 20, which would result in a 200ms hookflash. From ktTel trace :



077 161210.802 392 configxml board file [C:\Program Files (x86)\VoiceGuide\conf\Config.xml]
078 161210.802 392 1 config board file load start (len=8363)
079 161210.802 392 1 dx_setparm BOARD (1, DXBD_FLASHTM, &[20]) call , XmlPathBranch_Last2=[<Parameters_DxBd><Parameter>]
080 161210.802 392 1 dx_setparm BOARD (1, DXBD_FLASHTM, &[20]) => 0,

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The hookflash problem has been resolved, however the system is not detecting call progress, specifically disconnect tone when the caller hangs up.

This is a default installation, using analogue extensions with callers ringing in externally. I've attached a recording of the disconnect tone when callers hang up in the menu. Can you please advise what changes we need to make to ensure the system detects caller hang up please.





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Opening attached recording file in Audacity shows that this disconnect tone is:


ON for about 380ms and then OFF (silent) for another 380ms


The ON sound is a single frequency tone, about 425Hz (see Audacity's Spectrum Plot attached)


to have Dialogic card detect this tone please edit the tone definitions in VoiceGuide's ConfigLine.xml file.


Please edit these two tone settings:








to have these settings:





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