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Thread: Serial terminal for PDP-8/I?

  1. #1

    Default Serial terminal for PDP-8/I?

    Hi all,

    I'm implementing a few new peripherals for my PDP-8/I hardware simulation and wondered if it's possible to connect a RS232 terminal to the 8/I at baud rates faster than 100.

    For the 8/E, there's the KL8/E console control that offers an RS232 port with a configurable baud rate. However, this is an omnibus peripheral so can't be used on the 8/I directly.

    The ASR-33 interface on the 8/I has a fixed baud rate of 110.

    So, does anyone if it's possible to connect a terminal like the VT100 to the 8/I at > 100 baud using official hardware?

    Already checked:
    • DP01A: Not sure if it can be connected to the 8/I. Has different IOTs than the KL8/E so wouldn't work on OS/8's KL8E TTY driver.
    • DL8I (part of DC08): Made for the 8/I, adds seven lines. Not compatible with OS/8's KL8E TTY driver.

  2. #2
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    I can look up the hardware tomorrow. However, you could always write a new device driver for OS/8 to support compatible physical hardware if it is not supported currently by OS/8.

    Dave

  3. #3

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    Quote Originally Posted by fpw View Post
    The ASR-33 interface on the 8/I has a fixed baud rate of 110.

    So, does anyone if it's possible to connect a terminal like the VT100 to the 8/I at > 100 baud using official hardware?
    Depends on the meaning of "official hardware", I think. There are other DEC cards that could be substituted for the M452, to allow a different baud rate. (I also sell M452 replacement cards that allow various baud rates from 110 to 19200.)

    There are obscure jumpers on the M706 and M707 that allow different character sizes and other than two stop bits, which suggests things other than the usual ASR-33 sometimes got connected.

    There's even an obscure M850 card that interfaces to RS-232 instead of the current loop W706. (I also sell a W076 replacement card that does both.)

    The story for the 8/I, 8/L, and PDP-12 should be the same, AFAIK.

    Vince

  4. #4

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    We had several 300 baud CRT's connected to the 8i as the local community college. So Yes, it is possible. I can't say how they
    were connected, but they were hardwired.

  5. #5
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    The PDP-12 at the RICM has a home made M452 board that lets you select all baud rates between 110 and 9600.M452-replacement.jpg
    Member of the Rhode Island Computer Museum
    http://www.ricomputermuseum.org

  6. #6

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    Thanks for your replies! I'll go for the modified M452 then, i.e. letting the user configure the baud rate of that board.

    As for the CRTs on the 8/I, that was probably running TSS/8? That supports the DL8I, maybe it was that.

  7. #7

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    Quote Originally Posted by fpw View Post
    Thanks for your replies! I'll go for the modified M452 then, i.e. letting the user configure the baud rate of that board.

    As for the CRTs on the 8/I, that was probably running TSS/8? That supports the DL8I, maybe it was that.
    Yes, it was running TSS/8. I believe it had a PT08 for the incoming phone lines. But I know those 6 terminals were hardwired (3 TTYs
    and 3 CRTs at 300). They were in the main computer room.

  8. #8
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    Quote Originally Posted by tradde View Post
    I believe it had a PT08 for the incoming phone lines.
    I think that a PT08 is for just a single serial connection. That would take a lot of PT08s.
    Member of the Rhode Island Computer Museum
    http://www.ricomputermuseum.org

  9. #9

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    Quote Originally Posted by m_thompson View Post
    I think that a PT08 is for just a single serial connection. That would take a lot of PT08s.
    Must have been a DC08. Memory fails me more often these days.

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