I have a BCM 50 5.0 machine and I am trying to get it to work with my 6.0 CSE. The CSE 6.0 has nothing BUT 1140 ip sets on it, the BCM 50 5.0 has a mix of sets. When we place a call from the CSE to the BCM 5.0, the phone rings and you can answer the call, voice path works. When you call from the BCM 5.0 IP PHONES ONLY, the IP set on the cse rings but you can never answer the call, the hookswitch does not work and neither does pressing the button assoicated with the ringing line. If we place a call from my bcm 50 5.0 to the CSE via a tdm set, the call can be answered no issue. FW on all sets is current. I also have another BCM 400 and it can place calls to the CSE and vv, and to the BCM 50 5.0 and vv with no issues. I have never seen this before where you can't answer a ringing phone. Trace logs show the call ringing normally and its waiting for a human being to answer it, none of the buttons or the hookswitch work. Very odd...