Plug the USD slave clock out to the first audio interface slave clock in. (888/24 etc. if you have one or to the ADAT Bridge I/O) Hook up the ADAT bridge I/O word clock out to the ADAT sync device's 48k in and set the sync device to ext sync. Connect the sync device's SMPTE out to the USD LTC in and make sure the sync device is configured to send SMPTE. Set Pro Tools to internal sync and put it on-line. You do not have to configure the sync device in OMS for this setup as Pro Tools will receive the positional reference directly from the USD. Configure the USD as normal.