I've had better luck using OS api calls for serial ports. It's not portable, but it's the only way to understand the behaviour of the underlying driver, which c

I've had better luck using OS api calls for serial ports. It's not portable, but it's the only way to understand the behaviour of the underlying driver, which can vary greatly with different hardware. It's very hard to get a vendor to fix their driver and firmware when you can't tell them which API calls they're making a mistake in.