Please clarify if you could where are the inbound 46 channels coming from? In your drawing you have a SIP PBX and a TDM PBX at each location and each location has 23 channels. Depending on how the traffic is coming into each location could change equipment requirements. But as a General answer you would configure a SIP trunk between the two Adtran units and then a SIP trunk from each individual Adtran to each SIP PBX and then a PRI interface on each Adtran to the TDM PBX. As well as build a data connection on the T1 between the two sites. Now also depending on call flow you may have to have the SBC function on the 908E if the PTP connection is routed, and you need to call from SIP PBX A to SIP PBX B. Once I have more detail about the setup I can give you better examples.
I went ahead and flagged this post as “Assumed Answered.” If you still need assistance, I would be more than happy to continue working with you on this - just let me know in a reply.