I'm using a Keyspan USB-Serial adapter. The device shows up fine under /dev/ttyUSB0, but I'm having trouble connecting to it.
First, when I try "sudo cu -l ttyUSB0 -s 9600", I get a "./cu: ttyUSB0: Line in use" problem.
I looked under /var/lock, nobody owns it. I also looked at who's holding ttyUSB0, didn't find anyone. After some searching, I forced the permission of ttyUSB0 to 777. That allowed cu to connect, but I get no output on the wire.
Any suggestions? The serial link works on my laptop (same keyspan adapter) so I know that's not the problem.