Using machine generated modes on the HA5KBP station

A common cable for machine generated modes (such as PSK31, RTTY, JT65, FT8, etc.) at the HA5KBP station is a 3×RCA to 4-pin 3.5 mm jack plug, which can be used with smartphones and modern notebooks. Its color coding matches the following.

RCA color	Meaning
red	right out (from PC/phone)
black	left out (from PC/phone)
yellow	mic in (to PC/phone)

It's important that for most of the radios below, the RX/TX switch used for operating with the microphone and the signal sent along with the external audio signals are separated. So switching to TX with the button on the mike won't transmit audio signals send through the external inputs and vice versa.

Yaesu FT-7900E and Icom IC-7000

For both radios, the 6-pin DIN to 2×RCA + DB-9 cable can be used, the pinout is exactly the same. The layout of the RCA plugs match that of the common cable, and the DB-9 cable can be connected to an RS-232 serial port (either native or through a USB adapter) to switch between receiving and transmitting audio by toggling the RTS pin. Alternatively, a green push button is connected in parallel, so that can be used to trigger transmit manually as well. This solution is pretty rugged, and has been in use for years without problems.

RCA color	Meaning
red	transmitter in (to radio)
yellow	receiver out (from radio)

Although the Icom IC-7000 has a 13-pin DIN socket like the Kenwood TS-440 below, the pinout is completely different and thus incompatible. (You can fry the radio!)

Kenwood TS-440

This radio doesn't have a 6-pin DIN socket, so the Kenwood-specific 13-pin DIN to 2×RCA + 6-pin header cable must be used. Latter is mounted on a small (~5 cm by 5 cm) square prototyping PCB, and it can be used with a 6-pin UART cable to trigger transmit and receive. This is more of a proof-of-concept solution, especially since the ground is also hacked in a way that the whole construction is based on the idea that the audio signal shares a ground with the UART. Also, the connectors are not properly sealed.

RCA color	Meaning
black	transmitter in (to radio)
yellow	receiver out (from radio)