does the voltage increase or something
(acording to howstuffworks.com everything is connected in a parallel circuit and i thought this is how it happens)
more information in the link below
http://electronics.howstuffworks.com/telephone.htm/printable
2006-11-27 11:30:48 · 4 answers · asked by macgyver 1 in Consumer Electronics ➔ Land Phones
Jay is close, but off a little.
Home phones work on what is called a loop start circuit. Ground on one wire and battery (-48vdc) on the other. When you go off hook, current flow is detected at the central office on your phone line. Dial tone is applied and with the reciept of the first digit, dial tone is removed and the call is processed. When your phone is called, a ringing current 90vac 20 hz is applied to the pair and the bell is rung or the voltage is detected and ringing sound is supplied to a speaker. When you answer the call, current flow is detected at the central office, the ringing current is removed and the circuit is connected to the calling party.
2006-11-27 15:54:11 · answer #1 · answered by sharkbait 3 · 0⤊ 0⤋
things have changed a bit, but the basics are the same, and still work.
the phone company has a constant supply of low-voltage power on the line...the article says 6 to 12v..however, i cannot verify that as since i have DSL on my line, my constant voltage is higher, i do believe at one point 24vac was what i was reading. the ringing is sinply a higher voltage signal (90 volts ac..almost what comes out of your wall outlets) modulated at a lower frequency...20 hz. when the hookswitch is off and the phone is disconnected, the phone company can detect detect that it's hung up and then they send the low frequency higher voltage signal down the line. in the old days, the ringer would only react to this higher voltage signal and that in fact wound ring. the signals are still sent down the line the extact same way, with caller ID being sent in between the ring spike. most modern phones have circuits to detect the high voltage signal and generate a more pleasant ring...but the method is the same and hasn't changed. In fact, if you're holding on to a phone wire when a call happens to come through, you can get a bit of a jolt.
2006-11-27 20:32:09 · answer #2 · answered by Jay Moore 5 · 0⤊ 0⤋
I think they pass 48V AC down the phone wire
2006-11-27 19:46:42 · answer #3 · answered by amania_r 7 · 0⤊ 0⤋
Maybe a loose wire or something.
2006-11-27 20:11:49 · answer #4 · answered by J 6 · 0⤊ 0⤋