Hello again,
I have double check the red wires and the codecs, i checked them with ohm meter and i changed all of them just in case. the problem seems to be at the wire of my RRC-1258 Ver1. Every cable that i fixed the result is the same, display works perfect, PTT is working fine and modulation works, but when i stop talking to mic with PTT pressed a strong noise pass through my modulation, I Tried different capacitors bigger than 1μF at MIC as you suggest at your design with no better result. I was using those units with an Icom 706MkIIG without any problem. Please help me find what is wrong, Is there any other cable design for my old RRC-1258 ver 1 to eliminate this kind of interference on my modulation?
Thank you for you help.
Sv1gfu