Since playing with HDSDR and looking at what it can do I happened across Omnirig. Lo and behold Omnirig had an .ini file for my NRD-535D communications rx. I dug up an old RS-232 cable and a null modem adapter and gave it a shot. I was pleasantly surprised when I could tune HDSDR with the '535. Cool!
Here's the problem - it doesn't work in the opposite direction. HDSDR won't control the receiver. I've checked the settings using several instructive web sites no no avail. I even asked a local ham to verify my settings because he uses it (although not with this radio) and everything seems OK in my setup. It's just that it only works to control HDSDR, but if I change freq. or modes in HDSDR, it won't control the radio. I've checked the .ini file and it looks OK, even though I'd be surprised if the guy who wrote the .ini file had made a mistake. Plus I'm familiar with the programming for the radio as I wrote my own control program for it in C back in the day.
Yes - I have sync to Omnirig and from Omnirig checked amongst other required settings.
So, any ideas as to why it's only working in one
direction? I've exhausted all the resources on the web.