Sorry to be so scarce people... One client just turned into 4 (that client started 4 new companies), and each one is setting up new offices.... I'm far worse than swamped. I believe the first HP-IB drive in that line was the 7906, but it would be incorrect to make a blanket statement that "7906's were HP-IB". Specifically, the 7906A, B, C, and D were not HP-IB (they used a 13037 subsystem). The 7906H was strictly HP-IB. It also used a 13037 subsystem, but a board was added to the 13037 chassis to give it HP-IB capability. I was fortunate enough to obtain a few 13037's that include the HP-IB option (as well as a spare HP-IB option board as well). The differences between the 7906A, B, C, and D were mostly power supply and EMI/RFI shielding changes I believe. The only difference between a 7906D and 7906H was that you pulled out one (or two, can't remember) boards from the card cage inside the drive, and put in a microprocessor board instead which spoke HP-IB. Then of course you had to have the optional HP-IB board inside the 13037. As someone else pointed out, 7900A (and 7901) drives were never HP-IB. Just used a 13210 controller set. I used to have a 7912. It was HP-IB (and I would ASSume it was HP-IB only). Odd animal. Jay West