HowTo: attended internal call forwarding, configured but does not work

Current Asterisk Version: 11.25.1
Phones: Grandstream GXP1625 and GXP2140
Problem: Attended call forwarding does not work
When an external call comes in, we want to forward it attended.
We get the external call, pickup the phone, can hear the external caller, press the call-transfer key on the phone(s), enter the destination extension, BUT; a this point, the destination extension does not ring nor show the forwarded call in the display.
So we get no information on this forwarded call on the destinations extension. Question(s): HowTo configure FreePBXs extensionsnumbers to have this feature activated for all phones/extensions? HowTo check/prove this feature is (already correctly) activated in FreePBX? HowTo check in the phones admin area/webinterface which feature how to be configured?
Does someone know about grandstreams phones and how to activate/configure thisfeature`/function?
Thank you all for your highly appreciated support.
I am at the end with my Latin, as we say in german language. :wink:


try answering the external call, pressing transfer, enter the number you want to transfer to, then press send. it has been a while since i have used grandstream phones

Attended transfer was working for me on our Grandstream phones (2140, 2160, 2170) until I installed the latest firmware via EndPoint Manager 1.17 (which is Grandstream firmware ). At the same time, I also updated FPBX to the latest stable modules. I have one extension that can do attended transfer, but the others all do a blind transfer instead. I’m still digging to see why, but wanted to let you know you aren’t the only one.


I started seeing issues with calls being transferred by using the transfer button -> blf for the recipient of the call with firmware Could not pickup the call on the recipients phone although the call was transferred to that extension.

For me, this was resolved by creating a new EPM template. Sangoma Support tested various Grandstream firmware versions and could not duplicate the issue we saw in my environment. The unaffected extension was on a different template, which makes sense. :slight_smile:

Thanks @lgaetz for the help!

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