Phone sets the user side in telephone communication start and terminus, it is the user terminal unit of telephone network. Contemporary phone can realize terminal user conveniently the call between and communicate, be improved through coming to what the research of a lot of people mixes countless times more than 100 years and form. Although their style differ in thousands ways, but be like next basic functions commonly;
1, acoustical report and electroacoustic changeover function. Because want to undertake fast, remote communication, cannot convey directly sound, and must turn voice into telegraphic name first (serve as carrier with report namely) , believe report again to hind of the other side date is reductive make sound.
2, when advocate when making just take phone, switching equipment is due can know " someone should call " function, so that switching equipment makes good continue preparation.
3, send dial the function of signal. Automatic telephone machine dials through sending signal will direct the work of phone switching equipment just about, keep abreast of and build the connective between two phone.
4, the function of diabolo. Telephone in the other side namely when, phone function tells host with ring: "Somebody telephoned. "Somebody telephoned..
5, with the electric continue function between switching equipment.
In phone, the part that implements this 5 big functions is ordinal be: Send receiver, fork reed, dial (or by clavier) , phone bell and phone loop.
Microphone is a caddy that installing carbolic bead. There is a fixed electrode at the back of caddy, there is an oscillatory film in front (call oscillatory electrode) . When you speak to microphone, oscillatory film does the vibration that extent differs along with audio size variation, make impaction of carbolic bead from time to time (resistor is reduced) , loosen then (resistor increases) , make had shed the electric current between two electrode to also follow change thereby. such, audio size variation turn into the strong weak change that suits the telegraphic number that has transmission on circuit.
The main body of receiver is a permanent magnet that circles wired circle. The electricity of one's voice in speech that the other side transmits produces a magnetic field when passing coil, attract the tagger before magnet to produce vibration, sound. Oscillatory size decides to spend the bulk of the electric current of coil at flowing. This is why receiver can believe report date is reductive into audio simple truth.
When we call, the first movement is " pick machine " (send receiver to be taken from phone) . At this moment, bear the weight of on phone the share that sends receiver (cry " forked reed " ) can bounce come, make the circuit between phone and switching equipment puts through. Be like at this moment the machine line of switching equipment is available, send to phone successive " dialling tone " , it tells you: "I had been in on call, dial please! Dial please!!