Hi, I picked up an old IBM AT the other day and found a strange card in it. It's a full length card with an 8 bit ISA plug. It has two Burr Brown DAC800P-CBI-V ( D to A?) ICs on it along with a large IC marked TSC 7109CPL. (I have no idea what that one is.) There is also a small flat sealed Yuasa NiCad battery in the top corner of the card. It has 37 pin male connector on the back and it's marked "copyright 1983 MBC". Most of the ICs are dated 1986. It looks like it may be some kind of D to A convertor card. Does anyone know what it is for sure? Joe