Kenwood TS-450, 680, 690, 711, 790, 811, 930, 940, 950.
Kenwood sure had the SSTV operator in mind when they built this series of radios. They are by far the easiest radio to build an interface for. The 300 mV fixed level AF output is just right for the soundcard line-in level. Kenwood even disables the microphone if we use Acc2 pins 8 and 9 to key the transmitter.
Makeup a shielded cable about 5 or 6 foot in length from pin 3 and 4 to a stereo plug for Line-In.
Use another shielded cable the same length from pins 9 and 8 for the TX keying. Then a shielded cable about 3 foot in length from pins 11 and 12 to the gain pot R2/R3 and last a shielded cable about 5 foot in length from pot to the soundcard Line-Out stereo plug.