If you are referring to the remaining ports on the Signalink, none of them are needed for FT-891 interface. The 6 pin-DIN/RJ45 cable connects the Signaling to the FT-891 'RTTY/Data' connector. The USB A/B cable connects your computer to the Signalink. That's it. The other three Signalink ports are for circumstances when you might have to get creative with an older rig.