Why would only certain RS232 controllers work?

[WattsThat]

Well, turns out I got some good advice from an expert in the field.  The USB adapter with the FTDI chip did indeed work like charm.  And in Windows 10, no less.

It’s not that it has an FTDI chip, it’s because it supports TX/RX plus the other handshake signals of DSR/DTR/RTS/CTS and perhaps even DCD and RI all at the proper RS-232 required voltage levels.

If you’d tell us the brand and model of converter, we’ll know for the next time someone asks “which USB to RS-232 converter supports the old PC standard pin-outs and levels?”.

I know from personal experience the Digi Edgeport brand of converters are 100% reliable for all applications but most wouldn’t want to pay for them as they run about $100 US.

[gslick]

I know from personal experience the Digi Edgeport brand of converters are 100% reliable for all applications but most wouldn’t want to pay for them as they run about $100 US.

I have some Edgeport 4 and 8 port USB RS-232 devices from back when they were from Inside Out Networks, before they became Digi branded. The ones I have are implemented using old school traditional ST16C654 quad UARTs and MAX3243E RS-232 transceivers on the RS-232 interface side of the devices, with full support for all of the normal hardware handshake lines. I have never had any issues using these Edgeport devices all the way up through Windows 10 currently. If I had to replace them now I wouldn't want to pay the price for buying them new, but used eBay prices seem reasonable for devices that should just work reliably.

[Karel]

Well, turns out I got some good advice from an expert in the field.  The USB adapter with the FTDI chip did indeed work like charm.  And in Windows 10, no less.

I never use anything else than FTDI because so far I never had any issues on both Linux and windows.
Never change a winning team.