Amazon.com : RS232 Serial Port go to PS2 Converter for Scanner ASCII USB-HID Device (Read Out & Display) : Electronics
Keyboard Adapter Full Assembly: APPLE 2 RS232-PS/2 from RetroTechLyfe on Tindie
Amazon.com: Wiegand Converter Wiegand to USB Wiegand to Serial RS232/PS2/ABA/TTL, Serial to Wiegand Converter, Up to 128 Bits Wiegand Data, Android/Linux/Widows/iOS(USB) : Electronics
Serial RS-232 and PS2 Cables for Industrial Workstations - Hope Industrial Systems
NEW DB9 Female to PS/2 MDIN6 Mouse Keyboard Adapter Converter ** | eBay
USB to Serial Adapter Cable w/ Isolation - Serial Cards & Adapters