Using Netvanta 3430's to connect a p2p T1 and split voice and data.  Currently the p2p is connected to an IP Office and a Merlin Magix and it works fine.  The pbx's are set up as PRI and are using channells 18-23 for voice currently.  When we try to split the data off, I get one way communication on the PBX's.  The IPO can call the Magix and have 2 way conversation.  When the Magix calls the IPO, the phone rings, but there is no audio.  I have installed the 3430's and are using them just as a CSU and it works fine w/ my current PBX configs, but when we split the channells, the 1 way communication occurs.  Adtran thinks it maybe a "clocking" issue, but I kind of beg to differ, because it works as long as I don't split the channells.Any thoughts?

Figure it out damn-it!

This was probably covered by Adtran, but besides your BCHs 18-23 make sure the DCH, channel 24, is contiguous to your switches. The DCH is how the PRI communicates its messages with the Magix and IPO.

Do you have any DS1 test equipment that can capture the DCH messages for call set up and tear down? If you do this might provide some clues as to what might be happening.

Does this condition happen regardless of the channel quantity split?

....JIM....