Landlines: The Drama of Tracing a Phone Call

March 24, 2010 - By Jason Hamilton

How many movies, or TV shows, have we seen where the police are trying to catch the bad guy on the other end of the phone line? Someone tells the police officer “You have to keep him on the line for at least a minute!” And lo and behold, the bad guy has a stop-watch; he’s clocking that “1-minute”, too! The music tempo increases, your palms are sweating, your eyes glued to the screen….and the bad guy hangs up. Just seconds before the call can be traced. Really annoying, huh?

And then you find yourself asking, “Why does it take so long to trace a phone call? We live in the 21^st century, for Pete’s sake!” And you would be right in doing so. Truth is, we’ve been in the “21^st century” a lot longer than Hollywood would have you believe. So let’s start by asking this very important question: Why don’t the police use Caller ID?

The Caller ID on your telephone uses a feature called Last Call Return. With every call that is placed, a phone number, time/date stamp, and sometimes the identity of the bill payer, is transmitted. Just by you dialing a complete phone number, this information, that points back to you, is instantly put into the system. The same technology that goes into your Caller ID, is the same technology used to make a call trace. The public is privy to only a few details of that information. Welcome to the digital age.

When the need arises, federal, state, and local law enforcement agencies will contact the network operations center (NOC) for the local telephone company. The NOC will then provide all the details the police will need to know. And it doesn’t matter if the call was made five seconds ago, or 5 days ago. The information is still there. The NOC has more information at their disposal, however. They also can tell the police what town, central office (CO), cable pair, and the address of the originating caller. Pretty cool, huh?

“But what if the bad guy has some sort of digital-encryption-fake-number-device-thingy?” I will answer that by saying that he is fooling himself. The bad guy still needs to hook his miracle device to a cable pair, which will terminate in a switch.. There is no way to fool the switch into thinking he’s calling from a different office, or that he’s on a different cable pair. That’s basic electrical theory. I’ll make a concession to the movie-buff naysayers by making this hypothetical statement: He would have to have an insider in the phone company pulling strings for him. But because of all the security checks in the phone company, that approach would still end badly for him; and for whoever helped him.

The term “Call Trace” is kind of a misnomer in the modern age of the digital switch. Before the digital switch came into being the drama of tracing a call was real. And the drama could last for an undetermined period of time. When I first started working for the phone company, one of my mentors was tasked with tracing a phone call. This happened in the early 1970′s. Only in his case, it was a 911 call reporting a car accident.

A mother had run off the road and into a pond. Her child drowned while she was trying to get herself and her child out of the car. She did not know CPR. She found the nearest payphone but washysterically frightened. She did not know where she was and could not give 911 directions to her location. The 911 center called the phone company to report the issue. The tel-co already knew which trunk group the call was on, but the technician had the daunting task of using his Butt Set (you know, the over-sized phone set that the telephone man wears on his tool belt? That’s what it’s really called) to locate the specific cable pair, and then physically “trace” it through the CO to the cable pair that was leaving the office. At that point, they had a pretty good idea of where the mother was calling from. Sadly, they got there too late.

Not every call trace in the days of the old telephone company ended in tragedy. But they were full of drama. The digital age of technology has brought us speed, convenience, accuracy, and even more information that we probably want to know. So, the next time you watch a movie, remember that in reality, there is no FBI agent in the room telling a desperate mother to keep her child’s kidnapper on the line. If the kidnapper is stupid enough to call, he’s already been made.

And next time the Caller ID pops up on your phone, you, too, have just traced a call.