How did the first telephones work?

Answer 1

Knowing the sound give off waves, like ripples in the water, they travel into the mouth piece there the sound waves are copied by the transmitter behind the transmitter are carbon grains that when an electric current is traveling makes the grains vibrate and that alters the resistance of the grains as a whole. In this way the sound makes more and less current flow in the circuit in proportion to the sound.

At the other end was a coil of wire within a magnet attached to a diaphragm. The variations in current caused the wire to move in the magnetic field and so make the diaphragm vibrate in sympathy. Vibrations (as we learnt at the beginning) move air and this makes sound!

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The only problem with the above is Bell did not invent the "carbon transmitter" described above, His first telephones used a transmitter containing a corrosive liquid which could leak and make a mess.
The first phones were very simple. There was no dial and it was basically a box with a ear piece and voice piece. The person using it picked it up clicked the reciever and an operator came on asking who did the person wanted to to call. The operator completed the call. The first phones were sold installed in Hartford Conn in 1877 and the first exchange linking two cities was in 1883 between Boston and NYC. The group of operators in the exchange working at a large switchboard and connected it manually for the caller. Coin operated phones were made in 1889 and the first dial phones came about in 1923 in France.

Answer 2

1. you took the earpiece off the switchhook
2. you turned the magneto crank on the side of the phone to call the operator
3. a flap on the switchboard next to your line's jack dropped down
4. the operator plugged a plug into your jack and returned the flap to its up position
5. the operator flipped a switch to connect her headset on the line and asked "number please?"
6. you gave the operator the number of the telephone you wanted to call
7. the operator checked that the jack for that phone was empty and if it was plugged the plug on the other end of the cord plugged into your jack into that jack
8. the operator then flipped a switch to disconnect her headset and connect a ring voltage to the line being called, the switch was then flipped back to check if anyone answered, this would be repeated as needed
9. when someone answered the operator then flipped the switch to disconnect her headset and go out of the connection
10. you then talked into the mouthpiece on the telephone about whatever you wanted to
11. you hung up the earpiece on the switchhook
12. when either party to the call hung up a relay in the exchange detected it and lit a light on the switchboard near the cord connected to the plugs that are plugged into the two line jacks
13. the operator sees this light and unplugs the cord from both jacks, a weight under the switchboard pulls the plugs back down to their storage position ready for the operator to use them on another call and the light goes out

In these old telephones batteries in the telephone powered the microphone, in modern landline telephones a large battery in the exchange provides this power and there is no battery in the telephone.

It was slightly more complicated if your line and the line you wanted to call were on different switchboards in the same exchange or were in different exchanges completely, In the first case the operator had to connect you through an internal trunk line to the other switchboard and handoff the call to a second operator to complete. In the second case the operator had to connect you through an external exchange to exchange trunk or an external long distance trunk and handoff the call to a second operator, who might have to handoff the call to a third operator, etc. as needed to route and complete the call. Sometimes a long distance call could take several minutes to connect through and you could hear the various operators talking, etc.