Hmmm.....the link above is a Yaesu rig-to Amplifier Cable
W7YEN was the first person I wrote to about this approx 3wks ago. Whenever I have written to or purchased cables from him in the past, his response has been within 48hrs. Given that I still haven't heard from him I thought that he may be out of business. Guess I am too impatient.
Maybe he's too busy making other cables.
Reading the AT-600 PRO manual, LDG does not
supply a Kenwood cable for this unit.
Like the man said, this looks like exactly what you need:http://af6sa.com/projects/Kits.html#KTI-LR"Kenwood Remote LDG Tuner Interface"
Here's the manual showing the AT-600PRO hookup:http://af6sa.com/projects/KTI-LR.pdf