Why did this work?

[Mi_T_Sharp]

I am asking this out of complete curiousity, because with my engineering background I cannot figure out why this worked:

My cable modem wasn't working yesterday. This happens from time to time, and I usually unplug the power cable and plug it back in, which resets the device and then everything works again. This solution was not working.

I called the cable company, and they were going to send out a technician to look at it, because they couldn't see me connected from their end.

Anyway, as I sat there pissed off that I had no internet, my girlfriend suggested that I unplug the power cable AND the coax cable from the back, and then plug them back in. She said that the cable company told her to do this before and it worked.

I said I would try it, but it wouldn't fix anything. Of course, after doing this, the modem powered up properly and started working again.

Does anyone know why? Does anyone care?

(I thought that the cable might be feeding in some sort of voltage to the modem, and the modem may not have been designed to handle the voltage coming in when it is powered down, but someone at work told me there is no DC offset in a coax cable).