Our front desk receives a call and the caller id shows up properly. When we use the blind transfer (##exten) the caller id is not being passed. What do I need to alter to retain the caller id on the transfer?
I don’t think I actually have a wiki article on that right now. The gist though is that you need to enable sendrpid and trustrpid in both the [general] and peer definition sections of sip.conf. sendrpid is either going to be rpid or pai, depending on the phone model you’ve got.
It doesn’t work with all phones, and that’s on the phone vendor in question to address.