Screamer
maybe you are mad or you dont feel like you are really getting their attention. if anything will its loud sounds.
the human ear is a delicate instrument. its also usually pressed right against the earpeice on the telephone or they could even be wearing earphone type headsets. the human ear is most sensitive to sounds at 1000 hz and the pain threshold is 120 db. so far I have been unable to find out whether or not the telcos have decible range limits on any of their switching systems.
but there should be no need for you to be going this high unless you are out to hurt people. sounds at lower levels like screams, whistles, personal body alarms, or loud tape recordings will be effective enough.
the first few times you should try to get upper level managers and ceos on the line. soon they will be wary of answering the phone from people they dont know. after which you could harrass the company operators in call after call so that they either shut down for the day or have to switch their phone numbers.
you could try telling them first why you are doing it and then give them the loud sound. soon they will hang up on you before you can blast them.
theoretically you could hold their number hostage. first give them a taste of what you can do then demand that they not answer their phones on a certain day. if they do they will be blasted. be sure and tell the operators as they will be the ones most affected. be prepared for some heavy duty tracing as they will want you bad.
the downside of the screamer is that anyone around the payphone you are at will hear the sound too. even with rubber o-rings and pressing the pesonal body alarm tight against the mouthpeice some sound is going to escape. if you are electronically inclined you could hard wire something to a phone line and have a switch that simultaneously deactivates your earpiece and activates the sound. the problem with this is your loss of mobility even when used in combination with a beige box.
See Also: Screamer 2