ZyXEL Omni 56K Plus USB/serial modem

[perryh at pluto.rain.com]

> To me it looks like they are using some kind of propritary
> protocol. You could try and see if any of the endpoints,
> which appear like /dev/ugen0.x files respond with "OK" when
> you send "AT\r\n" to the endpoint ...

How would I go about doing that?  tip(1), or something else?
(In case it is not obvious, I am not all that familiar with
the USB support in FreeBSD.)