Trouble accessing USB modems on NetBSD 8.1 x86_64

[Jeffrey Walton <noloader%gmail.com@localhost>]

Hi Everyone,

I am trying to test some software on NetBSD 8.1 x86_64 (fully
patched). The software tests fine on Debian, Fedora, OS X, and
OpenBSD. The software opens a modem, sends some AT commands, and reads
some responses. There's not much to it.

I added my user account to both wheel and dialer groups; then
logoff/login. I inserted both a US Robotics modem and Conexant modem.
Dmesg shows the insertions:

umodem0 at uhub1 port 1 configuration 2 interface 0
umodem0: U.S.Robotics (0xbaf) USB Modem (0x303), rev 2.00/2.00, addr
2, iclass 2/2
umodem0: data interface 1, has CM over data, has break
umodem0: status change notification available
ucom0 at umodem0
ugen0 at uhub0 port 1
ugen0: Conexant (0x572) USB Modem (0x1340), rev 1.10/1.00, addr 2

I visited the umodem (4) man page [0]. I tried opening the modems
using /dev/ucom0, /dev/umodem0, ucom0 and umodem0. All of them result
in "No such file or directory." I also tried opening /dev/ugen0 anad
ugen0 with the same result.

The man page ucom(4) man page [1] says I can open /dev/ttyXX (dial in)
or /dev/dtyXX (dial out). /dev/tty0 hangs at open, and /dev/dty0 hangs
at open.

The man page ucom(4) man page [1] says I can use portno to find the
modem. The program is not available on the machine and is not
available for installation using pkgin.

I'm at the end of my abilities.

How do I open a USB modem on NetBSD?

[0] https://netbsd.gw.com/cgi-bin/man-cgi?umodem
[1] https://netbsd.gw.com/cgi-bin/man-cgi?ucom