How to Enable Callback on Unsuccessful Blind Transfer
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How to Enable Callback on Unsuccessful Blind Transfer in 3CX Phone System

3CX Phone System includes an automatic callback feature in Blind Transfer. If you perform a blind transfer and the recipient of the call is busy, then the call will automatically return back to you. This way you can inform the caller that the person they are trying to contact is busy and proceed to transfer to another destination.

Enabling the Callback Feature

To enable the callback feature, from the 3CX Management Console, go to “General” > “Global Options” tab. Under “System Wide Options”:

callback blind transfer

  1. Configure a unique DialCode to enable this feature. This DialCode must not conflict with other DialCodes that you have configured for your PBX.  For example *3*.
  2. Configure the timeout in seconds that the caller will wait for the destination to answer before the call bounces back. For example 10 seconds.
  3. Click “Apply”.

Using the Callback Feature

When you perform a blind transfer to an extension that is busy, if that extension does become free (hang up) before the configured timeout, then the call will return to the extension that initiated the blind transfer.

When an extension is configured to accept more than one call at the same time (under “Edit Extension” > “Forwarding Rules” > “Available” and “Available 2” tabs), the call will not bounce back, but will instead be handled according to that extensions forwarding rules (by default, if the call is not answered within 20 seconds then the call is sent is sent to voicemail).

If the transferred call is rejected by the recipient it will be directed to his/her voicemail.

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  1. Hi,
    is there anything special that I need to configure on Yealink Phones (T48G) to get this working?

    Right now my Yealink Transfer Settings are:
    – transfer.semi_attend_tran_enable = 0
    – transfer.blind_tran_on_hook_enable = 1
    – transfer.on_hook_trans_enable = 1
    – transfer.dsskey_deal_type = 1
    – transfer.multi_call_trans_enable = 1
    – transfer.tran_others_after_conf_enable = 0

    On 3CX the Feature is configured with Function-Code *7* and 20 Seconds.
    Redirect Rules for those Extensions are set to 30 Seconds.

    It’s working when I do an internal Call – it’s coming back after 20 Seconds.
    But if I transfer an external call it will always do what the Redirect Rules say (after 30 Seconds) – and never bounce back to the extension that initiated the transfer?

    Hope someone can help me on this?
    Andreas Schnederle-Wagner

    November 10, 2015 at 12:20 pm Reply
    • Charalambos Eleftheriou

      @Andreas, thanks for the question. Firstly if you have modified the phones template please revert it back to the default template as we can not predict behaviour with custom templates. Check that the ‘Automatically transfer call back to blind transfer-er when busy’ has the dial code *3* set and the time out is set to 5 seconds (or the time-out you require) under ‘Settings’ > ‘General’ > ‘Global Options’ tab. Then make sure that the extension you are transferring to has been set to ‘Send call to my voice mail’ under forwarding rules ‘Available’ tab for both the ‘No answer’ and ‘Phone is Busy’ sections. Remove the option ‘Different behaviour for internal calls’ if it has been set.

      November 10, 2015 at 3:37 pm
    • Hi,
      thx for your Answer! But unfortunately it’s still not working.
      Original Template, *3*, Send to Voice Mail …
      It’s not transferring the call back – it’s sending it to the Voicemail then … :-/

      November 12, 2015 at 7:24 pm
    • Charalambos Eleftheriou

      @Andreas. In this case you will have to contact our support team in order for them to investigate this for you. Please contact your 3CX Partner / reseller to open a ticket on your behalf if you do not have support contract with us.

      November 12, 2015 at 8:49 pm
  2. Craig

    I am not sure this statement is correct:
    “When you perform a blind transfer to an extension that is busy, if that extension does become free (hang up) before the configured timeout, then the call will return to the extension that initiated the blind transfer.”

    …if that extension does NOT become free…
    …then the call will NOT return to the extension…

    Either one would fix this. but the way it is now – if the recipient hangs up the existing call within 10 seconds – the new call will boomerang back

    March 11, 2016 at 11:39 pm Reply
  3. Frank Drews

    Anyway to have this callback feautre for forwards, where the recipient isn’t busy but doesn’t answer? This happens way more often here.

    July 11, 2016 at 3:34 pm Reply
    • Charalambos Eleftheriou

      @Frank, when a user does not answer the call it will follow the forwarding rule set under the ‘Available’ tab. You may though post this in our feature request section: and if it gets enough votes and is technically possible it may very well get implemented.

      July 11, 2016 at 4:28 pm
  4. Chris

    I cannot for the life of me find this setting. Does it still exist in the same spot? If not, where can I find it?

    July 21, 2016 at 8:34 am Reply
    • Charalambos Eleftheriou

      @Chris, if you are referring to v15 then this feature now can be found under Settings > PBX > Transfer Back on Busy section.

      July 21, 2016 at 3:19 pm
  5. Chris

    @Charalambos Eleftheriou, thanks for the response. The only mention of “transfer to the use that originally parked the call” (that I can see) is regarding Call Parking. This doesnt apply to Blind Transfers. Well, it doesn’t for me! Any suggestions?

    July 22, 2016 at 6:39 am Reply
    • Chris

      @Charalambos Eleftheriou, very sorry please ignore. I’m an idiot, found it under the very clearly labeled “call back” section. Thanks for your help!

      July 22, 2016 at 6:45 am