About Phonecell Mismatch

Hi, I have a AXT800 and running configured it at loop start reverse battery, i have 5 samsung tellular and 3 phonecell SX4e tellular. After connecting the call, the ports of the samsung tellular becomes ‘UNKNOWN’ to ‘IP CALL’, but the ports of phoncells never changes the ‘UNKNOWN’ state to ‘IP CALL’ state, whether the calls are connected and the clients are talking. Is it true that, Phonecell doesn’t work in reverse battery mode?? plz give me a solution.