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).

[LuckyTxGuy]

I can't answer the "why" but I can confirm that the coax removal trick does solve the problem at times. Like you, I can find no real logical reason for it to work but I am by no means any sort of electrical engineer or even slightly good at figuring out the "why's" and "how's" of many fixes.

[nuclear500]

Because often times devices that have a carrier signal will go into a "disabled" state when they disconnect from one another and when you reconnect, it goes back into an "enabled" state - its how the cable company even knows you are hooked up and why stealing cable eventually gets you caught - they know there is a carrier there that shouldn't be. This procedure essentially resets the carrier signal that might be haywire because the teleco equipment resets itself when the port goes disabled and then reenables.

Additionally, lots of devices, although "turned off" are still hooked up and actually drawing power, however residual and therefore there is the chance that a skewed memory bit (or whatever) remains and allowing the power to dissipate completely clears that memory.