The FT-8900 is a ruggedly-built, high quality Quad Band FM transceiver providing 50 Watts of power output on the 29/50/144 MHz Amateur bands, and 35 Watts on the 430 MHz band. It includes features like cross-band repeat, dual receive, VHF-UHF Full Duplex capability, and over 800 memory channels.

(taken from FT-450D manual)

A suitable cable can be made from a PS/2 extension lead, scrap PS/2 mouse or keyboard. Sometimes with the mouse/keyboard option, not all of the required pins are populated, so may not be suitable. Identify the pins with a multimeter (a croc clip lead is useful here.) Solder a DB9 plug on to the other end as above.