We do serial differently.

[Zaphod Beeblebrox]

On Thu, Oct 19, 2017 at 11:08 AM, Ian Lepore <ian at freebsd.org> wrote:

>
> Use the "callout" device, /dev/cuaXX, rather than /dev/ttyXX (which is
> the "callin" device).  The callin device waits for a call to come in,
> and that's implemented by blocking in open() until the modem/other-end
> asserts DTR (or DSR, I can never remember which end is which).
>
> So if it's hanging with /dev/ttyU0 use /dev/cuaU0.
>

Is the reverse true?  I have been using cuaU0.