Thanks for providing this pinout. I got my hands on a Ms Intellimouse trackball only to discover it won’t work on my 486 unless I have Microsoft 68666 adapter which sells for 5$ plus a thousand dollars shipping on eBay.

I was thinking of getting one of these ps2 bracket headers and modifying it instead for the correct pinout to my i/o cards com port. How cool would it be to be able to buy a bracket that had two 6pin din ps2 ports wired for Microsoft intellimouse and Logitech mouseman. I know there’s many adapters from each manufacturer but something like that would save a lot of headaches!

paradigital wrote on 2021-04-24, 14:03:

maxtherabbit wrote on 2021-04-24, 13:51:

I have several adapters, but none of them are marked. I also don't have a microsoft serial compatible mouse to test with. If you can identify a defining characteristic of the MS one I can see if I have it

From what I can find on the web, the MS adapter for this (and similar era) mouse will have 68666 stamped on it/moulded into the casing.

If you do have one that would be great, thanks.

I finally got my hands on a 68666, as well as what turned out to be an identical X03-55560 - a later version of the exact same adapter.

This pinout shown here is almost perfect but required two slight amendments:

TheMobRules wrote on 2021-04-24, 17:45:

[…]
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1       PS2_1 <--> N/C
2[  RD] PS2_2 <--> DB9_2
3[ GND] PS2_3 <--> DB9_5
4[ RTS] PS2_4 <--> DB9_7
5[ DSR] PS2_5 <--> DB9_6
6       PS2_6 <--> N/C

This is the corrected version:

1       PS2_1 <--> N/C
2[  RD] PS2_2 <--> DB9_2
3[ GND] PS2_3 <--> DB9_5
4[ RTS] PS2_4 <--> DB9_7
5[ DSR] PS2_5 <--> DB9_6
6[ DTR] PS2_5 <--> DB9_4
7[  TD] PS2_6 <--> DB9_3

Thanks for that, so you are saying that pin 5 of the PS/2 connector is actually connected to both pins 6 and 4 of the DB9 serial port? Providing both Data Set Ready and Data Terminal Ready signals.

I'll have to dig out the machine and try again!

paradigital wrote on 2023-10-10, 09:37:

Thanks for that, so you are saying that pin 5 of the PS/2 connector is actually connected to both pins 6 and 4 of the DB9 serial port? Providing both Data Set Ready and Data Terminal Ready signals.

I'll have to dig out the machine and try again!

Yep

Huh, different again from the pinout I got working. Now I'm wondering if this was yet another design, or if I just got somehow lucky. I didn't use DB9 pin 6 at all, maybe it's used as some sort of loopback for the driver? Although Win98 auto-detected the mouse fine with how I wired it up. And I definitely needed RTS connected to both the PS/2 clock and data. I was using a model 45717 ps/2 with serial compatibility mouse, which might make a difference.

snufkin wrote on 2023-10-10, 15:33:

Huh, different again from the pinout I got working. Now I'm wondering if this was yet another design, or if I just got somehow lucky. I didn't use DB9 pin 6 at all, maybe it's used as some sort of loopback for the driver? Although Win98 auto-detected the mouse fine with how I wired it up. And I definitely needed RTS connected to both the PS/2 clock and data. I was using a model 45717 ps/2 with serial compatibility mouse, which might make a difference.

I would suggest you try wiring up that mouse this way and see if it works matching the original MS adapter pinout. I strongly doubt they changed the adapter pinout between generations.

maxtherabbit wrote on 2023-10-10, 18:18:

snufkin wrote on 2023-10-10, 15:33:

Huh, different again from the pinout I got working. Now I'm wondering if this was yet another design, or if I just got somehow lucky. I didn't use DB9 pin 6 at all, maybe it's used as some sort of loopback for the driver? Although Win98 auto-detected the mouse fine with how I wired it up. And I definitely needed RTS connected to both the PS/2 clock and data. I was using a model 45717 ps/2 with serial compatibility mouse, which might make a difference.

I would suggest you try wiring up that mouse this way and see if it works matching the original MS adapter pinout. I strongly doubt they changed the adapter pinout between generations.

Will do, need to get a few other things out of the way first. Agree that within one company I'd expect them to have picked one way and stuck with it.

snufkin wrote on 2021-04-30, 12:18:

Right, just to finish off, I had a bit of time to actually wire something up, and I had the pinout wrong. But nearly right: […]
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Right, just to finish off, I had a bit of time to actually wire something up, and I had the pinout wrong. But nearly right:

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1Internal | Wire colour | PS/2 pin | Serial pin
2  pin 1  |    White    |       6  |  TD 3
3  pin 2  |    Blue     |       2  |  RD 2
4  pin 3  |    Orange   |   +5V 4  | DTR 4
5  pin 4  |    Yellow   |   GND 3  | GND 5
6  pin 5  |    Red      |  Data 5  | RTS 7
7  pin 6  |    Black    |   Clk 1  | RTS 7

Comparing with an actual MS serial mouse, the driver sets both pins 4 (DTR) and 7 (RTS) +ve. The other serial output (pin 3 TD) stays -ve. I checked the PIC data sheet, and the inputs will clamp to Vss (0V) and Vdd (+5V ish), to a maximum of 20mA. So, given then 100 ohms input resistance within the mouse, and the normally high output resistance of the serial port, I guessed that the connecting serial port voltages to the PS2 Clock and Data pins (which go to the PIC RA0 and RA1 pins) would be safe. Given that I was fairly sure RTS was used for signalling the mouse to ID itself, I changed the internal pin 3 to connect to pin 4 (DTR) on the serial connector. Then I connected a cable from pin 7 (RTS) from the serial connector to pins 5&6 on the internal connector (I thought I would try both together first, increase the clamp current capability).

Connected it to a serial port, rebooted, Win98 auto-detected the mouse and all was good. I did then try connecting RTS to just the Clock or the Data, but that didn't work, so both have to be connected.

I've only tried this by soldering a db9 directly on to the pcb, I haven't tried (don't have the right connector) connecting it via a PS2 connector. But I don't see a reason why it wouldn't work.

Hmmm, you prior diagram seems to match the pinout at this article ...

https://old.pinouts.ru/InputCables/MousePs2Se … al_pinout.shtml

Any clarity on if this link is incorrect?

Also, any idea if different MS models are wired differently? I have the "Wheel Mouse Serial and PS/2 Compatible" mouse (PN X05-51692; Product ID 83351-576-9044792-00000).

I am trying to use the cables online AD-M01 (https://www.cablesonline.com/mintodbps2to.html) but doesn't seem to be working. I need to spend some time and confirm the wiring pinout but it says "Straight Through" in the description which leads me to believe 1-1, 2-2, etc.

So I checked the pinout of the Cablesonline.com adapter and it doesn't seem to be correct based on the above...

1PS/2         DB9
21            1
32            NC
43            3 & 9
54            2, 5 & 7
65            6
76            NC

Just came across this thread.
I have documented the pinouts of about 5 different adapter types I have come across (sadly I've not found the right mice to go with most of them).
I can post some of that info here later, and can also get details as to the MS mice I have that work with the "alternate" MS adapter I have.

For now though, the info above is correct as to the MS 68666 adapter. It does seem that the pinout changed slightly for later models.
There's no part number on the adapters I have so let's just call it the MS "alternate".
The pinout is basically the same, except that PS/2 pins 1 and 5 are tied, but not connected to any serial pins.
Serial pins 4 &6 are also tied on that side.

I have 2 or 3 MS mice that only work with this adapter and NOT the 68666.
I assume that PS/2 pins 1 & 5 being tied signals to the mouse to use the serial protocol.