Have you ever been in an office or somewhere and wanted to make a free phone call but some asshole put a lock on the phone to prevent out-going calls? Fret
no more phellow phreake, for every system can be beaten with a little knowledge!
There are two ways to beat this obstacle, first pick the lock, I don't have the time to teach locksmithing so we go to the second method which takes
advantage of telephone electronics.
To be as simple as possible when you pick up the phone you complete a circuit known as a local loop. When you hang up you break the circuit.
When you dial (pulse) it also breaks the circuit but not long enough to hang up! So you can "Push-dial." To do this you >>> RAPIDLY <<< depress the switchhook.
For example, to dial an operator (and then give her the number you want to call)
>>> RAPIDLY <<< & >>> EVENLY <<< depress the switchhook 10 times.
To dial 634-1268, depress 6 X'S pause, then 3 X'S, pause, then 4X'S, etc. It takes a little practice but you'll get the hang of it. Try practicing with your own # so you'll get a busy tone when right.
It'll also work on touch-tone(tm) since a DTMF line will also accept pulse. Also, never depress the switchhook for more than a second or it'll hang up!
Finally, remember that you have just as much right to that phone as the asshole who put the lock on it!
(From the Official Phreaker's Guide)