Looks like the versions in 1990s ARRL handbooks (7404 for inversion of data lines).
It is different from the Kenwood OEM -- which used opto-isolaters.
The Kenwood interface used opto-isolators to eliminate ground loops associated with differentials in grounds between various pieces of equipment, such as the radio Power supply, computer, AC power line and radio.
You may or may not have success with a more simple circuit. The ARRL Handbooks showed different circuit versions for Yaesu, Icom, and Kenwood; the Kenwood versions also used opto-isolators. YMMV.
It is hard to make out the drawing, do you have a bigger readable version ?
From what I can make out, it should work fine if RF and Ground loops don't get you.
that's the whole issue with Kenwood radios. To eliminate the ground loop issue, most of the interfaces actually DO use isolated, opto-isolator coupling. (Some use isolation transformer isolation instead.) You might "get away" with a simpler interface is some situations, but that's not guaranteed. And might drive you crazy in trying to trouble shoot the problems along the way.