Nortel Annex Terminal Server question

I’m trying to figure out a pinout for a Nortal Annex Terminal server for a device using a standard RS-232 DB25 connector. After reviewing the pinout info from Nortel my customer is still unable to gain communication. The device(s) worked previously on a Synoptics 3395 terminal server card w/out incident. My device has xmit on black (2), rcv on yellow (6), grounds are red & green(4&5). Help?