Evan Doorbell's Classic Phreaking Tapes

Re:Evan Doorbell's Classic Phreaking Tapes by cperciva on Friday September 08, 2017 @01:35AM (#15198106)

Sorry, I should have specified more. This is a "potential entrant selects the person they're trying to visit; system phones the pre-programmed number for that occupant; occupant talks to the visitor and presses a button to let them in". In my building, I have to press 6 to make the door unlock.

Could a vistor play a very loud "touchtone phone 6" into the microphone and make the system think that the occupant pressed that number?

[ Parent | on HN ]

Re:Evan Doorbell's Classic Phreaking Tapes by mulmen on Friday September 08, 2017 @03:30AM (#15198475)

That would require the audio signal to be a single channel right? That or the residents phone would have to be very loud. I'm not sure but I think phones operate on a dual channel (tx/rx) setup which is what allows all participants to talk simultaneously.

[ Parent | on HN ]

Re:Evan Doorbell's Classic Phreaking Tapes by cperciva on Friday September 08, 2017 @04:56PM (#15203883)

I was thinking echoing. I don't know how loud a button tone needs to be for the entryphone system to accept it as an instruction to unlock the door.

[ Parent | on HN ]