Here is a catalog option and price list page from 2004 that refers to 3600 baud trunking being available in Q1 of 2003. It seems that 9600 trunking was already available at that time which would have been shortly before Q1 2003. So it would seem the first XTS5000's came out in late 2002. I would assume it would have been around that time... You can probably look up the FCC type acceptance number (in the service manual?) and find out from the FCC exactly, if you really need it.