Connecting a Model M to a Macintosh Computer

Libretto Simpatico

22 Mar 2019, 23:29

It is a pleasure joining your community. As a new member, I don't see a "Post New Thread" link so I will address my question here and seek your assistance and feedback. I discovered this site after my futile attempts in connecting a recently acquired IBM Model M 42H1292 to my two Macs: a 2011 Mac Mini (High Sierra) and a 2015 Macbook Air (Mojave). I also visited a local Best Buy to test connection with other Macs as well as Windows computers with no success.

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When connecting the Model M using a PS/2 to USB converter to either Mac, I receive the following notification:
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Would appreciate any of your insights.

Thank you.
Last edited by Compgeke on 23 Mar 2019, 21:39, edited 1 time in total.
Reason: Mod edit: Split into its own thread instead of being a reply to a previous thread

User avatar

24 Mar 2019, 22:31

You need to use an “active” USB adapter - I have had success with this one:

For Keyboard Mouse Male to Female Cable Adapter Converter Use USB to PS2 Cord Converter Adapter

User avatar

24 Mar 2019, 22:52

@Libretto Simpatico: Welcome to DT!

I have successfully used both the "Blue Cube" and the Adesso active PS/2 to USB adapter/converters with an IBM Model M keyboard and Mac computers.

I just did a search for the Blue Cube, and it appears to be no longer available. However, the Adesso is available, although it appears that you are already using that one.

Are you using any other cables or adapters in the chain from the keyboard to the computer? If your keyboard has an AT DIN-5 connector, I recommend using a short AT to PS/2 adapter.

If you are using a USB hub, use a powered hub.

Good luck!

Libretto Simpatico

24 Mar 2019, 23:40

Thank you for your inputs.

Unlike earlier models that came with detached cables, this 1995 IBM Model M 42H1292 comes with an attached PS/2 cable which I connected to the Adesso (which is advertised as an active converter) to the back of the Mac Mini as well the Macbook Air with no success. I also tried connecting the converter directly to the USB port on the Thunderbolt Display.

During the visit to Best Buy, I attempted connection with both the current model iMac and the iMac Pro. In all cases, I received the "USB Accessories Disabled" notification on the top right corner of the monitor as shown in the 3rd image. In attempted connections with current Windows computers, I receive similar notices alluding to excessive power or no notice at all.

If this Adesso converter is a dud and does not actively convert, would I continue to receive this "USB Accessories Disabled" notification?

To DT members who are currently and daily using a Model M with a Mac, how were you able to have both work together with no issues?

It'll be terrific to have this keyboard connected to my Macs to relive the wonderful experience I had using the Model Ms at the university computer lab to type last minute term papers in the 1990s.

Thank you.

User avatar

25 Mar 2019, 00:55

I found my IBM Model M 42H1292 and connected it to my mid-2012 Macbook Air with an Adesso PS/2 to USB active converter. The MBA set up the keyboard with no problem. BTW, I am running Mac OS High Sierra 10.13.6.

I tried it with and without being connected to AC power, and I tried both USB connectors (left and right sides). Everything worked.

The problem with your setup might be the converter. It is also possible that newer Macs and/or a different version of Mac OS do not function with this keyboard and/or converter.

EDIT: I also noticed that the label on the back of your Model M does not look like an original. I hope you acquired the keyboard from a reputable source. Do you know when it was last tested and shown to work properly?

User avatar

26 Mar 2019, 20:55

Honestly, I have a home-built TMK-based converter (using a Pro Micro) on my Model M and that works on my Macbook and my old eMac, no problems whatsoever. Sometimes cheapy PS2 to USB converters are not 100% right. I have had one with chatter or (since I live in Europe and more than half my collection is ISO rather than ANSI) the ISO key next to left shift is dead.

The only thing that I get a *low power* USB warning on is my phone, with a Lightning to USB OTG adapter. This actually works with my iPad, albeit mine is an old iPad and haven't tested with newer ones.

Yeah, DYI may not be your bag, but you can find Soarer's converters for sale online and that will provide much better performance and customization over a cheap converter.

User avatar

10 Mar 2020, 05:28

My main issue with this is that modern MacBooks, including mine, use USB C. It's irritating having to use two adaptors to make my keyboard work, but I can't find a single PS/2 to USB C adaptor out there, nor a USB C hub with a PS/2 port included. Any options someone else may be aware of? Or do I just need to suck it up and double-dongle the board?

User avatar

10 Mar 2020, 15:29

Here is my 5¢ answer. I never experienced any issues connecting one of my several ibm model Ms or FS to my hackintoshes since snow Leo to my last osx high Sierra. I used both blue cube active converter ps/2 and the same howard81 mentioned. Although I never tried to connect any kind kbd via usb c 3.1. the error message you got seems the same I got when I tried to connect my ibm F XT to Mac with a soarer's converter that had a bad wiring soldering. In other terms your Mac seems to say there is something wrong with voltage pin. Try to test your keyboard with a standard pc.
[strikethrough] myself, looking at your pics see something strange. I don't recognise a standard model m from the led panel.[/strikethrough]
Last edited by dcopellino on 10 Mar 2020, 23:11, edited 2 times in total.


10 Mar 2020, 22:52

You could always put the converter inside of the keyboard (like a Soarer's Converter or TMK/QMK converter) and just run a USB C cable out of the keyboard, so no external adapters will be required. I believe there's also some bluetooth conversion options, so no adapters or cables would be required at all in that case.

If your Model M had a removable cable, you could get away with just the one SDL to USB Cable and a USB to USB C dongle.


10 Mar 2020, 23:40

Bluetooth option is here- ,it is a full controller replacement.

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