I recently purchased a XEP100 from TechnologicalArts that works good.
The XGATE assembler has problems and I was able to finally develope a XGATE Serial transceiver. I recall serveral request in the past for an example of an XGATE Serial program. I excerted a part of my program to assist some friends and they though it would be helpfull for the forum...
The enclosed file (XG_TUT_02) may assist you in developement...