Subject: KENWOOD TH-series HT TNC Interconnection The following is a suggested circuit for connecting a packet TNC to a Kenwood TH-series HT. Included is the TH-21/31/41, the TH- 205/215/315/415, and the new TH-25/45 series HTs. The connections are as follows: A sub-miniature plug is used for receive audio. The tip of this plug is audio out; the sleeve of this plug is the common ground for PTT, transmit audio, and receive audio. A miniature stereo plug is used for transmit audio and PTT. Connect the middle "ring" of the plug to the TNC audio out through a 0.2 uf cap (for DC isolation). Connect the sleeve of the plug to the TNC PTT. The plug's tip is unused. Set the TNC audio for 50 to 80 mv audio output into a 2K ohm impedance.