How Does A Landline Telephone Work?
The word ‘telephone’ comes from two Greek words tele (far) and foni (voice) and it can be defined as an instrument ‘that transmits and receives sounds from a long distance’.
Although Alexander Graham Bell is credited with the invention of the telephone, the issue is still disputed. Other claimants to be the first inventor of the telephone are Antonio Meucci (Italy), Johann Philipp Reis (Germany), Elisa Gray (USA) and Tvidar Puskás (Hungary).
In the year 2002 the US congress acknowledged that if Antonio Meucci had been able to pay the $10 fee to maintain the caveat after 1874, no patent could have been issued to Bell.” In other words, it was Antonio Meucci who first invented the telephone.
But it is still widely believed that it was Graham Bell who invented the telephone and the first spoken words over a call were “Mr. Watson, come here, I want to see you.”
The basic principle is like this: a phone has a microphone which is a device that converts sound energy into electrical impulses; a speaker to convert electric signals into audible sound and a cable that connects two or more telephones to each other.
There are two states a telephone can be in: on hook (idle) and off hook (in use), and in both the states, different components of a telephone work. When a caller tries to get through to someone, he picks up the receiver from the cradle—this automatically puts the telephone on the ‘off hook` mode–and and dials a number. This creates electric impulses which travel to the nearest telephone exchange, which in response sends the caller a dial tone to indicate readiness.
When a number is dialed, it creates electric signals, which are then read at the telephone exchange. The exchange recognizes the fluctuations in the electric current received and matches them with the corresponding number.
But the other number still doesn’t know that somebody is phoning, because it is`on hook’ and is not receiving any current from the telephone exchange. La solution is a capacitor .Here a capacitor comes into play.. It blocks the flow of the DC current (from the exchange) but allows the AC current to pass through it. The exchange detects this and sends an AC signal to the ringer of the other telephone and tring tring! And here is a phone call! Then there are also lines which are called ‘trunk lines’ because they connect telephone exchanges.Category: Technology