[GreenKeys] Support for serial ports

[Bryan Brodie]

I was able to connect a Telebyte device to an old Dell server and use
my TTY as nature intended, but I never got it to work with my Mac Pro
tower with a serial card installed. I was never able to configure
MacOS/UNIX to transmit / receive over the serial port at less than
9600 baud. I had believed that the USB to serial solutions didn't work
for TTYs, but it sounds like some of you guys have it working in UNIX.
If anyone has ever successfully connected a Mac to a TTY, I'd love
more details (D.R. House?)

Also, isn't it George Hutchinson's birthday soon? Happy Birthday
George! (and thanks again for the ASR35 you sent me a few years ago).