I have a problem with third party phone Interbell IP250 registered to CUCM7. I cannot make a call transfer when calling from Interbell to Interbell (after pushing transfer button subsequent pushed number buttons "are sent" as DTMF in RTP). When I am calling from Cisco SIP IP phone to Interbell, it is working - I can make a call transfer to other phone from Interbell.
Is it possible to solve it? Call Forward All (CFA) activation from Interbell IP phone is not working, too. I can activate it only in CUCM for Interbell IP phone.