This is a 3 way clockport hub. It allows to plug up to three devices using the same Amiga 1200 clockport. This design is based primary by Rob Cranley design and also on the Ian Steadman 3 way clockport (in both case with their permission) but modified to include a 74245 buffer to improve signal quality on each clockport.
Devices that can be plugged:
Real time clock
Usb interface (RapidRoad – Subway)
Sound Card (Melody pro, etc)