Telecommunications :: Telephone Radio Television Microwave Satellite

The transmittance of words, sounds, images, or info in the clear of electronic orelectromagnetic signals or impulses. Transmission media include the telephone(using wire or optical bank line), radio, television, cook, and satellite. Datacommunication, the fastest growing field of telecommunication, is the sour oftransmitting data in digital form by wire or radio. Digital data can begenerated directly in a 1/0 binary code by a computer or can be produced from avoice or visual signal by a process called encoding. A data communicationsnetwork is created by interconnecting a large number of development sources sothat data can flow freely among them. The data whitethorn consist of a specific item ofinformation, a group of much(prenominal) items, or computer instructions. Examples include anews item, a situate transaction, a mailing address, a letter, a book, a mailinglist, a bank statement, or a computer program. The devices used can be computers,terminals (devices that transmi t and receive information), and peripheralequipment such as printers (see Computer authority Systems). The transmission lineused can be a convention or a specially purchased telephone line called a leased, orprivate, line (see Telephone). It can also take the form of a microwave or acommunications-satellite linkage, or some combination of any of these several(a)systems.Hardware and SoftwareEach telecommunications device uses hardware, which connects a device to thetransmission line and software, which makes it possible for a device totransmit information by the line.HardwareHardware usually consists of a transmitter and a cable interface, or, if thetelephone is used as a transmission line, a modulator/demodulator, or modem. Atransmitter prepares information for transmission by converting it from a formthat the device uses (such as a clustered or parallel positioning of electronicbits of information) to a form that the transmission line uses (such as, usually,a series arrangeme nt of electronic bits). Most transmitters are an integral cistron of the move device. A cable interface, as the name indicates,connects a device to a cable. It converts the transmitted signals from the form undeniable by the device to the form required by the cable. Most cable interfacesare also an integral element of the sending device. A modem converts digitalsignals to and from the modulated form required by the telephone line to thedemodulated form that the device itself requires. Modems transmit data through atelephone line at various speeds, which are metric in bits per second (bps) oras signals per second (baud). Modems can be either integral or external units.An external unit must(prenominal) be connected by cable to the sending device.