Apple USB keyboard won't connect to iMac

You’re welcome.

I can”t remember exactly which year model or version of keyboard it was, but some of those old keyboards came with a USB extension cable that was required with some Mac’s. Do you remember if that old keyboard came with a USB extension cable? If it did try using that cable with the keyboard.

Test the keyboard plugged into one of the 2019 iMac’s USB-C ports using a USB-C to USB-A adapter..

den.thed wrote:

Test the keyboard plugged into one of the 2019 iMac’s USB-C ports using a USB-C to USB-A adapter..

Aren't the USB-C ports on a 2019 iMac Thunderbolt ports?

When is the last time you tried it on your Windows PC?

You would think so, but maybe not if the OP has a bus powered external drive or something else plugged into the other USB-A port.

If you look real close, you will see a notch in the keyboards plug that corresponds to a ridge in the female end of the extension cable.

I have a couple of these cables around here, and I've seen that notch many times. I always just took it as Apple being proprietary. I mean, the connectors appear to be the typical USB but for that notch which just seemed to be a fitment thing.

I never would have put 2 & 2 together for this issue as I've never experienced the OPs problem.

Wow! Great call, my friend. 🙂

Thank you.

Even stranger, is that the keyboard plug worked in the OPs old windows laptop and not the 2019 iMac.

On that one, I can only guess that the laptop top has loosiey-goosiey USB ports compared to the iMac's USB ports.

You're welcome. I for one can't think of any reason the keyboard would work on a PC and fail to work on two different Macs. Maybe someone else will have an idea.

They are Thunderbolt/USB-C ports and USB-C is just a faster variant of USB.

Plus they provide more power than the USB-A ports,. Which is why I suggested using one of them for the old USB-A keyboard.

Can't hurt I suppose. Hard to believe a USB Keyboard requires much power.

That's awesome... I'm glad to have helped.