BIG BROTHER CABLE TV

JUSTIN (SAME NAME AS YOURS) WRITES... How does the cable TV company know how many TV sets I have hooked up to their service? I called them about a service question and they knew I had 3 without me telling them.

Well Justin (same name as mine), welcome to Ask Jim. I’m not sure I can tell you technically how they can tell you how many TVs you own, but I can give you a guess as to some of the methods they might use. These are going to be guesses based on electronic systems, such as fire alarm and security, that I have installed in the past.

One thing that is not clear in your question is what equipment you have. For instance, do you have a cable box? Do you have a cable box for every TV? Lets start with the assumption that you have one cable box for each TV. Each cable box will probably have some type of internal address like an electronic serial number. The cable company will send out electronic probes that will look for these electronic serial numbers. As each cable box is “pinged” it will answer back with it’s own address. Depending on how sophisticated the inquiry is and what information the box tracks and stores, it could be telling the cable company when the TV is on, what channels are watched and when. I’m not real sure how they would determine a specific address belongs to a TV in your house as opposed to the house next door unless they assign that address to you when they first install the cable and box in your home. Often there is a SKU number on the box somewhere that they can scan (or just write down the number). That way they have your box number in their system. This would be the simplest of scenarios.

Now let’s assume you have one cable box that feeds all three TVs. In that case, the cable box probably has the capability of monitoring it’s output. One brand of fire alarm system I have installed has the ability to not only poll all the devices installed and ask them what status they are in or command them to take a certain action, but the system can tell how much wire is between each device and where, in the circuit, there are splices. This is done by measuring minute differences in voltage and current.

There is also the possibility that there is something in each television that the cable company can “ping” that will tell them how many televisions are in your household.


Ever since there has been cable television, there have been people trying to steal it. I’m sure the cable company has gone through great lengths to detect unauthorized televisions on their system, not to mention the vast sums of money they could make my selling such information as number of TVs in a household and what they watched and when they watched it. (Not that they would ever actually do that, would they?)