Well, I am chugging along on this project. After fixing a few bugs, I now have a program that will read single blocks off the tape. Somewhere the docs got confused, they say that bit zero is MSB and bit 7 is LSB, a la IBM 360. But, the data I am getting is clearly the opposite bit order, so I will reverse that. Also, I am not detecting file marks, but see a block with zero length. So, I need to look at that. Could easily be a wiring error. But, I manually reversed the bits and I get VOL1 and HDR1 records of 80 byte length, and then data records of 8192 length. So, with just a little bit more tinkering, I think this thing is going to work. It IS a nightmare, with a 44-pin TSOP memory chip glued upside down on a piece of perfboard with wire wrap wires soldered to it. It was the only suitable memory chip I could find. 64K x 16, I'm only using one byte worth. Jon