Hi,
If you are going to use buttons for transfers only (and not origination/dial or status monitoring), then you can use dummy information in the channel name, you do not need to even use SIP/xx at all. This is because transfers will use the extension and context settings exclusively, for example, you could have something like:
[IT/DoesNotExist]
type=extension
extension=1234567
context=dialout-context
That button will work for transferring calls to 1234567.
You could also use Local channel if you want origination/dial to work, but then you will have to create a user with the same external number:
[Local/1234567@from-internal]
type=extension
extension=1234567
context=from-internal
Best regards,
