I need to buy a 9 pole mini din plug (male) to create a ps2 -> quadrature mouse adapter but I'm a little concerned the socket I'm connecting to is non-standard:

Rear of an Archimedes 440/1 keyboard [Angled view displaying notch better2

The reason I think this is the top 3 pins are not evenly distributed and the data sheets I look at for ordering online have them evenly distributed.

So my questions are:

  1. Is this socket standard?
  2. Are the datasheets wrong?
  3. Could I buy a 10 pin, and just pull one of the pins out of the plug?
  • \$\begingroup\$ The middle row is also not evenly distributed, although it's close enough that you could probably force it. \$\endgroup\$
    – Dave Tweed
    Jun 15, 2020 at 13:47
  • \$\begingroup\$ So are you saying the socket in the photo is non-standard @DaveTweed? \$\endgroup\$
    – John Hunt
    Jun 15, 2020 at 14:11
  • 1
    \$\begingroup\$ No, I'm just making an observation based on your photo. What exactly is the piece of equipment? \$\endgroup\$
    – Dave Tweed
    Jun 15, 2020 at 14:27
  • \$\begingroup\$ search for mini din connector leads to ebay.com/itm/… ... it is for Promedia GMX \$\endgroup\$
    – jsotola
    Jun 15, 2020 at 21:43
  • \$\begingroup\$ @DaveTweed this is the back of an Archimedes computer keyboard - and you're looking at the mouse socket. In this case it's a 440/1 system built around 1987 I think. The Archimedes line of computers used a non-standard mouse system called 'quadrature' - really weird. I'm using my Arduino to translate a ps/2 optical mouse into the right protocol for this. I've ordered a 9 pin minidin with flylead from RS components, it wasn't cheap but I didn't fancy soldering the mini-din. The Archimedes was one of the first 32 bit personal computers and was the first to use an ARM chip. Very cool, v.fast. \$\endgroup\$
    – John Hunt
    Jun 16, 2020 at 9:02

1 Answer 1


Is this socket standard?

Pinwise, yes, it seems to me that all 9-pin mini din connectors are that way, with an uneven first row, which is also found in the 10-pin model. If there are no differences in dimension, there shouldn't be any problems using a 9-pin din on it. Although that happens to be my experience, the fact that the datasheets indicate otherwise would make me second-guess myself.

Although, it does not seem to feature the two little notches near the bottom, common in the mini din connector, which might make it incompatible.(EDIT: A new picture shows that it does indeed have the notches.)

Are the datasheets wrong?

Well, it seems to me that they could, but it is hard to say, really. You should look for a datasheet with measurements to see if it really is non-standard.

Could I buy a 10 pin, and just pull one of the pins out of the plug?

I don't think the two bottom row pins would necessary align if you remove the middle one of a 10-pin. But perhaps with some force you could, although it would not be ideal.

  • \$\begingroup\$ Note - I think the notch doesn't show in the photo clearly.. the top is cut out to a depth of a few mm within the circle. \$\endgroup\$
    – John Hunt
    Jun 15, 2020 at 14:14
  • \$\begingroup\$ I meant these two notches near the bottom. \$\endgroup\$
    – Funest
    Jun 15, 2020 at 14:17
  • \$\begingroup\$ Thanks - it has those, I've added another photo that shows them much more clearly (in hindsight that first photo was really misleading!) \$\endgroup\$
    – John Hunt
    Jun 15, 2020 at 14:18
  • \$\begingroup\$ Looking at it now, I see no reason to believe that a standard 9-pin wouldn't work. If need be, the 10-pin might even work in a pinch. \$\endgroup\$
    – Funest
    Jun 15, 2020 at 14:20
  • \$\begingroup\$ Perfect, thanks for your help! \$\endgroup\$
    – John Hunt
    Jun 15, 2020 at 14:24

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