Can't transfer an external call from one extension to another

I have a Draytel 2800VG router with two FXS ports set up as two extensions (201 and 202) with PBXes. External inbound calls are routed via a ring group so both extensions ring.

What I can't seem to get to work is to transfer a call from one extension (201) to the other (202). I press the ## quickly but all that happens is the calling party hears the # tones. The call isn't being put on hold for some reason.

Calling from one extension to the other works fine.

Do I need to configue anything specifically?

RE: Can't transfer an external call from one extension to another

Try different settings of dtmfmode for your extensions.

Thanks. I eventually got it working. I had to try all sorts of combinations and in the end had to set the dtmfmode on the router voip ports to SIP INFO (Cisco format) originally they were set to inband. I then left the extension dtmfmode set to Auto.

Hopefully that will not mess up my ability to navigate through the voice menus when I call my bank.