Wednesday, October 05, 2005

Wireless on TV

Well this is the first posting, so if you happen to find this, let me know what you think...

My fiance last night called me and told me to catch Law & Order:SVU. She was wondering if the things that happened in the show relating to wireless calls were possible. The reason why she wanted my opinion is that for the past 10 years now I have designed, optimized and maintained wireless networks all over the US. If it comes to wireless technologies I either know the answer, or know someone else who would be able to answer that which I might not yet know about.

The premise of the show was a little girl tucked away in some pornography hell hole. She got out of one room, only to be trapped in an outer room. She did find a cell phone and was able to call 911. By the way, any cell phone -active or inactive- can call 911 as long as it can find a signal. So they started to try and track the little girl via the signals the cell phone transmitted to the towers.

Now they did mention early on that this was not one of the new phones that can be tracked by E911. That is a mandate that wireless companies in the largest 150 cities in the US be able to track emergency calls down to a specific accuracy (how accurate is a ratio, 30 meters some of the time, 100 meters most of the time). The idea is exactly this type of situation where people need help but can't say exactly where they are, either in a trunk of a car kidnapped, or on some highway in nowhere crashed into a tree. But only phones sold in the past few years have the technology on most wireless systems, and this one didn't.

So what could they then do? Well, all calls are transmitted to at least one radio tower. This tower covers a general area of a city, like here somewhere in Brooklyn. But that can cover many buildings, blocks or miles. Not exactly what they needed. The phone itself was lost by the previous owner, and was no longer activated, but again since all phones can call 911 the little girl could call them, but the cops could not call back to the phone. Here is where the system got a bit off.

The perp (I just like saying that) had somehow managed to install a virus in the switch that would "bounce" the call from tower to tower, so that one call looked like Brooklyn, then the next call looked like Queens and so on, and so on. That way the phone would not be able to be traced to a particular sector, and his secret lair of hideousness would never be found. This is where the writers finally started using poetic license.

First, the only way to talk to a switch is via its OSS (operational support system) 99% of the companies in the world will never put any public internet ports to a switch as the information on them is extremely sensitive and their lifeblood - your billing data. The perp (still loving it) would have to work for the phone company, or know someone who did. These are usually run on Unix systems, never windows, so the typical hacker would not be able to send an email with "click me now" type trojan horses. Is it possible to do this? Very unlikely, maybe 5-10 people I know of could hack there way in, run a program undetected in a Unix shell that has no direct port to the internet, and leave no trace of their activity.

Next, wireless calls just don't that far, especially in cities like New York. These phones are basically overgrown walkie-talkies. It has to be within the pathloss of the tower in order to talk. Yes the system could direct the call from one tower to another as that is exactly how you calls gets handed over from cell to cell while you drive and talk - public service break: don't do this if the call requires your attention, as then it doesn't go into your driving!!!! pull over and do one or the other please, ty=) - So getting a call into a basement of a building would be tough enough for one cell site, let alone another several miles away.

Now can anyone just track your calls? Well, there are features in your phone that disable location based services unless you are in an emergency call. Get out the manual - I know you might not have it anymore, so look online - and if you are afraid of big brother following you on your call - NCIS had this on the same night - even though your not talking, then just turn it off and your phone doesn't relay the location information needed by the system to track you.

Well, that is it. I plan on using this blog to talk to anyone and everyone about the benefits, problems and just any other silly topic about wireless technology. If you have any questions about something, let me know. As the name says this is what I know, and I love helping people understand the mystery behind that nasty bill they get every month.



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