[Yaesu] Connecting TNC2 to FT817

[Eddy Lamote at bigfoot]

Dear all,

Just made a cable to hook up my TNC2 to my ft817. Measuring signals on the cable without
connecting to the TNC, all signals are present. But once connected to the TNC the received audio 
seems vanished (looks like to much load). Transmitting is working fine (ptt as wel as transmitted 
audio is fine).
The TNC is working fine if I use it with a other tranceiver.

Hope somebody can help me out what can be the solution for this.

73,
Eddy ON4AEY