Re: Icom 7100
The IC-7100 needs only a single USB A to B cable.
That radio has a built in USB hub and audio CODEC that handles both serial CAT data and TX/TX audio.
There is a very thorough guide written by Clint Chron that includes IC-7100 settings (IC-7100 starts on page 8 as I recall) in the files section of this forum:
73 - Mark - K8MHW
'A RigPi Enthusiast!' - I am not otherwise affiliated with MFJ or RigPi