I don't think I've seen an answer to this question. Is H/W flow control set for the port. That would explain it. I don't recall if N1MM has flow control as an option or not when setting up the port, but the port settings in the device manager do.
If that is not the answer, then we need to look elsewhere. Is there any other software besides N1MM that can possibly be using serial ports? If so, don't bring them up and see if it goes away. Then bring them up one by one to figure out who's doing it. If that doesn't help, go here (https://www.eltima.com/products/serial-port-monitor/) and download the monitor. IIRC, they have a 14 free trial. It will help you find out who is messing with the serial port for the radio. I can't tell you how many really bad actors (not just ham programs) that are out there for serial ports. I have caught programs opening every port up to 15 times to scan and see what ports are available rather than using the registry as they should - dumb programmers. That drove my radio nuts because it would mess with DTR/RTS. I have caught programs opening every port and playing with modem control and constantly sending data to see what responses it gets to find their devices and causing all sorts of havoc - those programmers should be fired and sent to McDonalds to flip burgers - that is all they are good for. Programs should never send data to devices they don't know they own. I've gotten to the point of looking at firing up virtual machines so I can control what hardware the bad actor programs can even see. I really wish M$ would put ACLs in place for the COM ports. Then there's the whole serial enumerator idea (again someone's bad idea to treat serial ports as plug and play) causing havoc with mice. Thank M$ and FTDI for perpetuating that horrifically bad idea. Sorry for the soap box, but I was trying to give you an idea of just how badly serial ports are treated in Windows by both M$ and the programmers out there. 73, Joe On Jul 10, 2021, at 14:01, Frank Stein <fst...@ieee.org<mailto:fst...@ieee.org>> wrote: At Field Day this year, the K3 TX light started flashing when we loaded N1MM to use RTS=PTT to send .wav files. This only occurs when RTS=PTT is set on the rig. I thought it was a bug in N1MM but it also does this when using N3FLP's logger and the flashing corresponds to the polling rate (which N3FJP allows one to set). This is not a bug in either program since I get the same response when I use the K3 Utility and select Terminal Tab. Why would polling the rig cause the TX light to flash and the receive audio to momentarily drop? This is not a temporary initiation of the USB-RS-232 connection. And more importantly, what setting is wrong that is causing this? I have tried a different computer with a rs-232 port and I get the same result. Thanks, Frank W4TG fst...@ieee.org<mailto:fst...@ieee.org> ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com