Got the same problem with my D700.
Still not able to get any of my laptop/PC to transmit or receive using the D700, with built in TNC. Took MY laptop to a friends and nothing worked.
MY D700 worked on ALL of his laptops/tablets. They were running WinXP and Win10, they were so annoyingly simple the one, the Win10 system, just worked once the RS232 was plugged in. No setup required
SO, we have decided MY radio works. The Laptops do not. I can see no reason why the cables and D700 are all ok, on any Machine but on my laptops they do not work.
There must be something wrong with the data side of my USB ports, as I am using a USB to RS232 converter cable as we did on my friends machines, but I cannot think where to look or what to look for.
PLEASE can anyone offer any help as I have no clue what to try next?
Many thanks for any help you can offer Vaughn