Kenwood TK-8180 Interfacing Settings - 28-May-20

In the Extended Function/AUX Tab, set the following:

DB-25 pin  4 = Aux I/O 9 Input, Ext PTT (Voice)
DB-25 pin  5 = DI Input, Ext Data or Tone
DB-25 pin  6 = MI Input, External Mic   
DB-25 pin  7 = Ground  
DB-25 pin 22 = Output, TOR, or possibly COR if assigned. Use this to 
               detect no signal or tone on the frequency before transmit.

In the proper KPG software, the Extended Function/Modulation Line Tab, 
set the following:
 
MIC PTT: Mic Line = Connect, MI2 line = Connect, DI Line = Disconnect, 
QT = Yes, STE = Yes.

External PTT (Voice): Mic Line = Disconnect, MI2 line = Connect, 
DI Line = Disconnect, QT = Yes, STE = Yes.

DI is the Data Input, should be used for CTCSS / DCS.

You will have to tell the radio to enable the DI path during the front 
or rear PTT (transmit) control. The above programming table has not yet 
enabled the DI path for the rear external PTT. You assign the active or 
enabled functions per the Service Manual. The Extended Function Modulation 
Line Tab in the manual and software should provide enough information to 
get you going.

If you need channel steering you can program a few of the other AUXI/O pins.

This information was surreptitiously provided by Skipp, of course.