Hi Hans.
Thought I'd report my grounded PTT Out on TX test results here in a new topic ... that I suspect will be short lived.
Firmware: 016 QMX: Rev 1 low-band
I reproduced your LED +3.3 volt test on my bench similar to what you described to test your QMX and the grounded PTT out on TX functionality. My test failed, I could not get the LED to light unless I physically shorted plug tip to barrel (connector removed from the QMX) with a wire. So I suspect that the issue, sigh, is with my particular instance of QMX.
From there, I changed band configuration to +5V PTT OUT on TX (disabling ground on TX) on all bands. In this mode, I indeed measured +5 v between ring and barrel upon keying up the QMX. (I haven't looked at the manual recently, so hopefully that's what I should measure at those locations).
For grins and giggles, I decided to test the QMX with both +5 V and ground enabled on TX for PTT Out ... not being sure what to expect in this case. In this configuration, no joy on lighting the diode w/ 3.3V potential barrel to tip, but also no +5v present on TX between ring and barrel, albeit an odd configuration combination (that I suspect is undefined ... or presents itself as a wormhole to another universe?).
So I have to deduce that it's my particular QMX that's not behaving ... and I really needed that functionality to work for my setup, grrr.? I had been looking forward to that being enabled in your firmware for quite some time and so was excited when I saw that appear on your fixed issue list.? Hopefully, when I open up the QMX I'll find a bad solder joint, an open resistor, or perhaps a faulty socket that can be easily repaired. Some hints on what I should test for w/ QMX on the operating table may be helpful.
I appreciate very much that you took the trouble to go back and re-test your QMX to confirm that the firmware is indeed working as intended!!!
73!
Roy - KI0ER
