I just spent an enjoyable day at the local ham fest with my father - digging through boxes of other peoples junk. I'm a sucker for weird electronics, especially when it's in the free pile, and so I am now the proud owner of two Parallel to Serial interface boards and I'm left wondering what they originally came out of.

The boards are populated with some intriguing chips (which is why I nabbed them); assuming my quick googling is correct - an EF6809P (an 8-bit MC6809 CPU), an EF6850P ACIA, three EF6821P PIAs, and an AMD AM9128-20PC static RAM.

So obviously the chip complement seems to support the board label as some kind of a parallel to serial interface, but to what? Below are some snapshots to hopefully help identify the board.

First a view of the component side of the board (note the 50 pin connector J4) component side

Next, the assembly number and board description (sorry for the lack of definition here, the camera simply wouldn't pick up the silver grey lettering) board description and assembly number

The CPU, ACIA, RAM, one PIA an an unidentified chip (26A1063/A) AM2716DC EPROM. chips

And finally, the edge of the board (probably 2 RS-232? and 1 Parallel?) connectors

So, anyone having any brain-waves?

  • 5
    Looks like a full-blown computer rather than just an interface. The labelled chip is most likely an EPROM. The logo is vaguely familiar, too – scruss Oct 5 at 21:42
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    The EF6809P is a 6809 CPU, not a 6800. Those are very different, and that will be especially important if there's a ROM there to disassemble, as U32 appears to be. – Curt J. Sampson Oct 6 at 0:18
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    Since based on the socket size, use and configuration U32 appears to be a ROM, I would start by dumping that. (You can do that quite easily with an Arduino.) Start by scanning it for strings, remembering to clear all the high bits for that scan, and that alone may tell you exactly what the board is. – Curt J. Sampson Oct 6 at 0:28
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    If there’s a possibility it’s a whole computer, maybe try connecting a terminal to each of the serial ports and check for a prompt? – Tommy Oct 6 at 15:04
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    It's seems likely to me that it is in fact a "Parallel to Serial In" board, what it seems to say in the second picture. It would have been used to connect serial printers to computers with parallel interfaces. – Ross Ridge Oct 7 at 5:40

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