You'd need a ADB-to-USB adaptor (also called a "protocol converter"). It should have a Apple Desktop Bus (ADB) port in one end and a USB port (or cable) in the other.
The most common ones are:
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Hasu's. It is programmable so you can change keymap. You can also make one of these from a Pro Micro (or similar board with ATmega32u4 microcontroller).
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Drakware. Pretty recent one with 3D-printed housing.
* The
iMate is often available on eBay but pricey because I think they stopped being made some time ago. They stem from twenty-twentyfive years ago when Apple just had switched from using ADB to USB.