开云体育

What Tom said.? It's the way many HTs are keyed as well.

I built a cable harness roughly similar to what Ian described, hooking it to a Raspberry Pi 4B with a USB audio dongle.? The PTT side of things is kind of a mess, with some apps allowing the use of the GPIO pins and some forcing the use of a serial port DTR / RTS modem lines, which of course have the wrong polarity.? So it's a couple of switches and an inverter chip to let everything be plugged in at once.? I also have a 736R, so the switches also control which rig the lot hooks to.?

In hindsight, I think I would stick with the modem lines control, and not use the otherwise-convenient GPIO pins.? I think the modem interface is universally available among the apps (Direwolf, WSJT-X, FLDIGI, JS8Call, QSSTV), where only a few can do GPIO.?

The problem with the Mike input is one of inconvenient cabling, and the sensitivity to the setting of the mike level control.? The jacks in the back of the rig are fixed volume, so you can configure the software once, and then just use it with no tweaking needed.? Audio out goes everywhere; it's just the audio in that has the problem.

Greg KO6TH