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Thread: "Computer Systems" device. What is it?

  1. #1
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    Default "Computer Systems" device. What is it?

    I acquired this a few weeks back. It looked curiously like a computer but I don't think it is a computer but perhaps a peripheral tester or possibly a rack-mount front panel. Does anyone know what it might be? I have further pictures at http://vintagecomputer.ca/computer-systems-computer/

    Unfortunately, "Computer Systems" is generic enough that my Google skills can't find anything. Any help is much appreciated.

    Computer Systems - sm.jpg

  2. #2

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    From some of the settings on there, I'd hazard a guess that it's some kind of memory-tester device.
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  3. #3
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    6/8 bit data and nrzi/phase along with variable block size makes me think it is 1/2" tape related
    but the wierd thing is I don't see any I/O out of the box at all.

    If you set it to 'random' and open loop, I would think it would at least blink the lights.

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    I suspect that there might be an attachment through the large square hole in the back to the WW sockets, but that's just a guess.

    The weird thing is that the "block length" is just a plain old analog pot. Not even marked with calibration.

  5. #5
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    The large square in the back is part of the puzzle. Here's a picture of the rear "port" with hex bolts which I thought was a little weird. It just goes to the back of the wirerap board but this is area is directly connected through the wire rap board to the ribbon cables that go to the main board. Sadly, the original owner has passed so his son had no idea what it was for but it was an item that was cherished and kept through all these years.

    Computer Systems - rear port.jpg

  6. #6

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    It is some type of test instrument. It looks to be for some type of communications test device. What type of components does it have inside. The date codes might be an indication of what.
    Dwight

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    I would hazard a guess that it is, or at least incorporates, some kind of parallel-to-serial UART functionality, and if I absolutely had to lay a nickel on it I'd say it's some kind of test pattern generator/diagnostic tool for testing telecommunications equipment. It's really hard to say exactly what it does without laboriously trying to trace out that wire-wrap maze in there because all those ICs are really low integration DTL parts that each only supply a couple gates. Without a schematic there really isn't much to give it away.

    (It's pretty easy to look up the motorola parts, there's the datasheet floating around that explains almost all of them in one document, but the U6A909759X is kind of a rare bird. Again, totally guessing, maybe using at least some of those as static or shift-register "memory". Maybe its job was to generate a binary pattern, clock it through whatever it was testing, and run compares on what it gets back?)
    Last edited by Eudimorphodon; June 1st, 2019 at 07:06 PM.

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    I'm with Al on this one--the legends all point to some sort of 1/2" tape exerciser/test device. So not serial, but character-parallel with parity.

    The NRZI/PHASE refer to the two common types of older tape recording NRZI (non-return to zero, invert on ones) for 200,556 and 800 cpi 7-track and 800 cpi 9-track. PHASE - phase encoding, usually used on 1600 bpi 9-track drives. The later technology, not covered by this device is GCR (group code recording), used at 6250 cpi.

    Since it obviously connects before the tape formatter (i.e. direct to a "bare" drive), it's anyone's guess what make and model drives were intended--and how they connected to the WW pin area. You really need a manual for this thing.

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    NRZI and phase (Manchester) encoding are used for all sorts of applications, but the "Format" switch may well be a giveaway that it's intended for exercising tape drives. Ultimately it really is hard to guess without the manual. I'm particularly curious about the "Transfer Rate" knob that appears to have settings for internal, external, and single-step clocking. It's largely that which made me wonder if it might be for some kind of transmission line loopback testing.

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    Quote Originally Posted by Eudimorphodon View Post
    NRZI and phase (Manchester) encoding are used for all sorts of applications, but the "Format" switch may well be a giveaway that it's intended for exercising tape drives. Ultimately it really is hard to guess without the manual. I'm particularly curious about the "Transfer Rate" knob that appears to have settings for internal, external, and single-step clocking. It's largely that which made me wonder if it might be for some kind of transmission line loopback testing.
    So what do you make of the 6 bit and 8 bit settings? Looks like 7 track and 9 track to me. "Block" and "Continuous" would also fit tape drive applications.

    But it could be transmission line, or telecomms too or some bit of kit that nobody's considered. We don't even know if the interface is serial or parallel. Maybe we could hook this thing up to the "Dumbkopf I"...

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