When I had a TS480, I needed a short cable, about 20 inches long
to go from the body of the rig to the control head which I had on
the desk. I found out that yes, it's an RJ12 you need. I think
it's a direct one to one correspondence no wires crossed over
from one plug to the other. However, I now have the TS590 so am
no longer in need of the short cable. The only one I could find
for sale was an 18 foot one which I bought at the time from HRO.
73, Jim WA6EKS