This model uses same MiniDin6 data cable as many Yaesu transceivers. For CAT control it uses a classic RS-232 DB9 connector and requires RS-232 levels Digirig configuration.
The matching cables are listed under FT-480 kit:
Manual can be found here.
Working settings reported by the operator:
FLRig:
(In wsjtx I then just select the FLRig option)
FT-450D settings
D-TYPE - USER-U CAT RTS - Disable CAT TOT - 3000 CAT RATE - 38400 Needs to be in USB-Data mode No VOX settings