Phil wrote: <I need to switch my K2 mic input between two mic sources (TNC audio and a "real" microphone). Both have the default "Kenwood" pinout.> I'm very pleased with my NCS-3240 Multi-Switcher. Switches mics, speakers, computer lines, keyers, etc. Very versatile. http://www.ncsradio.com/m_switch.html Terry, W0FM