The SIIG / IBM 39Y8988 is a USB‑to‑Dual‑PS/2 adapter cable, originally supplied by IBM but manufactured by SIIG. It allows you to connect a PS/2 keyboard and PS/2 mouse to a computer via a single USB port
What the 39Y8988 Is
A USB → PS/2 converter for legacy peripherals
Supports two PS/2 devices (keyboard + mouse)
Uses a single USB Type‑A plug
IBM FRU: 39Y8988
IBM Part Number: 39Y8986 (often paired together)
Typically branded IBM but produced by SIIG
Connectors
USB Type‑A (male) → host computer
Two PS/2 female ports (purple for keyboard, green for mouse)
Purpose / Use Cases
Connecting older PS/2 keyboards and mice to modern systems
Useful for:
BIOS configuration on servers
KVM switches requiring PS/2
Legacy hardware labs
Replacing failed OEM adapters