Recently bought the Anytone AT-778uv without the programming cable, just happen to have al the parts somewhere 🙂
Made the interface according this site : http://iz3zvo.altervista.org/build-program-cable-anytone-at-5888uv-intek-hr-2040/

But couldn’t get it to work. After a long search on the net, I found a possible solution and tried it. It now works!
The trick is adding a diode in the line between data and TX (I have a CP2102 chipset on the converter). See the image below.

I used a 1N4001, but 1N4148 is also good.