I have a couple of these units weather station base units with USB.
The older one has a serial-USB smd chip on-board and a relay. The newer one has the chip built into the board and covered with a black blob. The older one appears in with $ lsusb as:
Bus 004 Device 002: ID 1941:8021 Dream Link WH1080 Weather Station / USB Missile Launcher
and used to show up with $ ls /dev as a hidraw device.
.
That was until the last “apt-get upgrade”. Now it’s still there with lsusb but gone from /dev
.
How to get it back:

A few links to solving the USB problem

Adding new vendor and product IDs to an existing USB driver
http://www.ha19.no/usb/

UDEV
http://andy.hillhome.org/blog/2007/02/05/using-a-umts-card-on-opensuse-102/

R-Pi notes
http://www.raspberrypi.org/forums/viewtopic.php?f=9&t=5867