Canon mx850 series Error Number :

OMG! Mine was also plugged into the phone jack at the back of the computer. I was on my way out the door to buy another printer! Thank you so much to TreasonGM for fessing up so that I could fess up also :)

I had the same problem. I had moved my printer and when I hooked it all back up, there was an annoying clicking sound, the "in use/memory" light was flashing and there was no communication with my pc.

This is a tad embarassing, but if it helps someone, so be it lol. I had plugged everything in without looking.... my usb cable was plugged into the phone jack >.<.

Check all your connections.... then check them again ;)