> Sorry. The dty(4) manual page is at
> http://www.FreeBSD.org/cgi/man.cgi?query=dty&apropos=0&sektion=4&manpath=NetBSD+1.5&format=html

Thank you!

After reading the manual page, I get:
/dev/ttyXX	dialin		blocks waiting for carrier
/dev/dtyXX	dialout		does not block

I guess the benefit of blocking is to make it simple for getty to wait for
a terminal/modem to be connected, and the purpose of not blocking is to be
able to communicate with a modem/device without carrier.

I noticed though that open("/dev/ttyXX", O_RDWR|O_NONBLOCK); made read()
read nothing where open("/dev/dtyXX", O_RDWR); made read() read data.  Do
you have an idea why?

Ben