* Know Few Things About Mobile Phones.
1. Who invented mobile phones ?
Like many other inventions, the mobile phones is the product of hard work and research of many inventors.
It was as early as 1900, when an inventor named Reginald Fessenden made his first wireless call. He was the first one to transmit human voice using radio wave, using digital signal form one radio tower to another.
In 1947, an engineer named William Young along with another engineer D. H. Ring started work on how a person can move round from one radio tower to another and still be on the call. It took 10 years before this become reality.
Richard H. Frenkiel and Joel S. Engel were successful in building a network that could support moving around with a cell phone. But there were issues.
Finally in 1973, Martin Cooper came out with first commercial cell phone. It was heavy and big like a brick. But improvements were repaid. Today, we have sleek mobile phones which can be connected almost anywhere.
2. Why can’t we Switch mobiles when the flight is about to take off or take on ?
Mobile phones release electromagnetic waves. The safety system and other equipment in the aircraft also operate on the basis of certain frequency of waves. Problem can arise if the mobiles transmit waves of same frequency as the equipment. It can send wrong signals or no signals, confusing the pilots.
Switching of mobiles is a prevention step. It has not been proved so far that mobiles create problem in the equipment and system of the aeroplane. But as a precaution, crew in the Aeroplane asks the passengers to switch off mobiles at the time when the aircraft is about to fly or land. After reaching a certain height, the chances of frequency getting mixed is less. But many aeroplanes don’t allow using mobiles at all on the flight.
3. How do mobile phones work ?
A mobile phone or a cell phone works by sending signals through the air. There are special towers build on the reads that catch these signals and send these to the person you are calling from your cell. The microphone in the cell phone converts these signals into sounds and your voice will be heard!
4. How does a landline telephone work ?
A telephone is different than a cell phone. Unlike cell phone, the telephone is connected to a wire at one end. It also sends signals like a cell phone does. But it sends signals through wires instead of air. These wires are laid under the ground and carry these signals to the person you are calling. The microphone in the phone coverts these signals into sound.