deh@ENEEVAX.UMD.EDU (Douglas Humphrey) (07/27/86)
I am reminded by this machine of the hack that you can do to any regular telephone, in which you place a PLL (phase locked loop) in the phone, and change the wiring on the switchook so that the phone can be taken off hook without the removal of the handset. When calling the phone, you transmit the tone that the PLL is looking for down the line. In most cases a connection to the target phone is made during the 'quiet' period of the interupter (the thing that determines your ringing cycle and timing), allowing the PLL to see the audio tone and answer the phone before it actualy rings. Even if it hits on the start of a ring signal, all you wil will hear is a brief blip of a ring from the phone once. Now the phone is off hook, just as if someone had answered it. Think about how sensitive phone microphones are; with amplification, you can hear anything said just about anywhere in the house. Modern technology is moving to make this impossible, but slowly. Most ESS systems will not connect the voice path to the local loop (your phone line) until after the signaling (ringing) has been answered, so in that case this would not work. Large parts of the country are still on crossbar, and in fact there are areas that are served by ESS systems which actualy are on #5 crossbar with electronic translation, and they may never go to real ESS. In this world where people will but poison in cold capsules just for fun, I would recomend that you carefully check out any device that you place in your home that allows for ANY level of remote control. Will it shoot cyanide at you while you sleep ? Hardly likely. But do be on the lookout for some sort of code that does the 'listen in on the house' trick WITHOUT the bleep or the 30 second timeout..... Paranoid ? No. Who's asking ?!? Doug
hes@ecsvax.UUCP (Henry Schaffer) (07/31/86)
> I am reminded by this machine of the hack that you can do to any regular > telephone, in which you place a PLL (phase locked loop) in the phone, and > will hear is a brief blip of a ring from the phone once. > ... > Now the phone is off hook, just as if someone had answered it. Think > about how sensitive phone microphones are; with amplification, you > can hear anything said just about anywhere in the house. > > Modern technology is moving to make this impossible, but slowly. > ... > > Doug I believe that this is known in the trade as an "infinity tap". My understanding of the origin of the term is that you can be any distance away from the premises and still listen in. --henry schaffer n c state univ