> Both are marked "Frontier TEchnologies Corp. AdCom 2-M Controller", one is > also marked "Version 3" (this one also has a holder for a coin cell on it) > and the other one "Version 5". There's also a Z80-SIO and an 8253 on each > board, and the Version 3 one has an 8255 as well. Some info at: http://www.frontiertech.com/aboutus/aboutus.asp