Hacking Doors

by Clark W. Griswold

I thought it would be fun to share some interesting things I've learned about something we've all seen, dealt with, and sometimes cursed at.  I'm talking about those telephone security systems in the front of apartment buildings.  You know what I'm talking about, those damn phones - you have to pick up the receiver and push a button and wait for your friend/relative to pick up the phone, and then decide whether to let you in the building or not.

Then they push a magic button, and the electric lock on the front door opens for a few seconds, and you have to hurry and put the phone back and run to the door and open it before the buzzing stops.  I'm not talking about the simple intercom types, but the ones where you hear a dial tone, and the button you push speed-dials their apartment phone number (dial tones, can you see where I'm going already?).

I started to get curious when I saw how my friend lets people in when he gets a call from the lobby on his phone.  When whoever it is says "I'm downstairs, let me in" the resident then pushes a button on his phone and holds it for two or three seconds and lets go.  The security phone downstairs senses this signal and energizes the electronic lock from my friend holding down the 6 key on his phone for a few seconds and letting go.

All fine and well, you say, but what does this do for my curious mind?  Well to begin with, most of the security phones in the front of the building have a standard telephone keypad built in, but you cannot get any tones when you push the buttons, except for the two or three digit code you put in to speed-dial the individual apartments.  When you pick up the receiver to either put in the speed-dial number or push a single button next to the particular person's name, try using your pocket tone dialer (RadioShack or equivalent type that you put up to the mouthpiece and send DTMF with) and see if you can make a local or even long distance call!  Wow!!  A free phone to call anyone you want.

Of course, you would want to be careful on making a number of long distance calls that would be billed direct to that number, but using calling cards, PBXs, extenders, or just local calls should not arouse any suspicion, or raise the phone bill of the party who gets the bill for that number.  Keep in mind that you are at the front door of people's residences, so just being there for an extended period of time might be a little obvious, so use discretion.

Also, try dialing an ANI number and see what happens.  If you get a valid number, have someone try to call you at that security phone and see what happens!  Sometimes it will ring on its own, and sometimes it may be an actual extension of one of the phone numbers in the manager's apartments.  If you really want to get back at the manager cuz he kicked you out or something, I suppose you could run his bill sky high with 900 numbers, but that would be illegal.

Just one more thing...  You pick up the receiver, push the button for your friend's apartment, and no one answers.  Now what???  Well, the next time you are in his apartment and he lets someone in, notice what button(s) he pushes on his phone to open the door.  The next time you try to get in and he is not there, whip out your trusty pocket dialer, hold it up to the mouthpiece, and push the same tones for the same length of time, and I bet the lock will open on the door!  If you don't believe me, try it for yourself.  The look on my friend's face when he's late to meet me at his apartment, and I'm sitting at his apartment door, inside the building waiting, or just all of a sudden knock on his door without calling first to be let in, is worth a million bucks.  He still can't figure it out.

Since I figured this out, I can either get free phone calls and/or get into about 30 percent of the buildings that I mess around with.