Arduino-based adapter to use a USB keyboard with an apple computer with ADB
http://ww1.microchip.com/downloads/en/AppNotes/00591b.pdf https://developer.apple.com/library/archive/documentation/mac/pdf/Devices/ADB_Manager.pdf https://developer.apple.com/library/archive/technotes/hw/hw_01.html#Licensing https://vintageapple.org/inside_o/pdf/Inside_Macintosh_Volume_V_1986.pdf