Satellite Communications: How does the telephone works?

A microphone (colloquially called a mic or mike) is an acoustic-to-electric transducer or sensor that converts sound waves, a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a level sufficiently strong to be heard, or the sensation stimulated in organs of hearing by such vibrations, into an electrical signal (any time-varying or spatial-varying quantity). The signals are then sent through the phone network to the other phone and converted by an earphone, a small loudspeaker designed to be held in place close to a user’s ears, or loudspeaker (speaker), an electro-acoustic transducer producing sound in response to an electrical audio signal input, back into sound waves.   Telephones are a duplex communication system, which means they are a point-to-point system composed if two connected parties or devices communicating with one another in both directions simultaneously. The telephone network allows any telephone in the world to communicate with any other. It consists of the following worldwide net of: telephone lines/circuit (or just line or circuit within the industry), a single-user circuit on a telephone communication system; optical fiber cables; microwave transmission, the technology of transmitting information or energy by the use of radio waves whose wavelengths are conveniently measured in small numbers of centimeters (microwaves); cellular network, a radio network distributed over land areas called cells, each served by at least one fixed-location transceiver as a cell site or base station; communications satellite (COMSAT), an artificial satellite stationed in space for the purpose of telecommunications; and undersea telephone cables, a cable laid on the sea bed between land-based stations to carry telecommunication signals across stretches of ocean, connected by switching centers (telephone exchange or telephone switch), a system of electronic components that connects telephone calls.Each telephone line has an identifying number called its telephone number, a sequence of digits used to call from one phone line to another in a public switched telephone network. To initiate a phone call, a connection over a phone network between the calling party and the called party, the user enters the phone’s number into a numeric keypad, a set of buttons arranged in a block or “pad” which usually bear digits, symbols and usually a complete set of alphabetical letters on the phone. Graphic symbols used to designate telephone service or phone-related information in print, signage (any kind of visual graphics created to display information to a particular audience), and other media include ! (U+2121),  (U+260E),  (U+260F), and  (U+2706). Unicode (U) is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world’s writing systems.Modern telephone, particularly “smart” mobile phones, a high-end mobile phone built on a mobile computing platform, with more advanced computing ability and connectivity than a feature phone, have many other capabilities besides being originally designed for simple simultaneous voice communications. They can also: record spoken messages through an telephone answering machine (TAM), or message machine (previously known as an ansaphone, ansafone, telephone answering device (TAD)); send and receive text messages (texting), the exchange of brief written text messages between fixed-line phone or mobile phone and fixed or portable device over a network; take and display photographs, or video (videotelephony, comprising technologies for the reception and transmission of audio-video signals by users at different locations, for communications between people in real-time), and surf the Internet, where a system of interlinked hypertext documents can be accessed, which is the World Wide Web (WWW, or W3, commonly known as “the Web”).