I have a wireless networked HP printer and was getting this error: Unable to communicate with device (code=12). I ran hp-check, hp-setup, hp-plugin, etc. After a few days' worth of frustration, I've figured it out.
The key was this:
http://hplipopensource.com/node/216
So after running
Code:
snmpwalk -Os -c public -v 1 ip.address.of.printer 1.3.6.1.4.1.11.2.3.9.1.1.7.0
I got this message: Timeout: No Response from ip.address.of.printer
Then I remembered...
