Non-computer tools used to transmit and receive include conventional mail, telephone, facsimile (fax), radio and television. It is important to compare and contrast computer- and non-computer-based communication systems.
The mail system makes it possible to send a letter or package to the address of any person around the world. Delivery of mail is dependent on road, rail and air transportation systems. Mail systems have improved steadily, especially with the development of machines that can sort letters. Further advances in technology have given rise to faster methods of postal handling and delivery.
The telephone system transmits sounds or speech between distant places along telephone lines. It is a convenient method of communicating with people around the world. The telephone depends on the receiver being available to accept a phone call.
Fax machines transmit and reproduce documents by means of signals sent over telephone lines. The fax machine scans the document and converts it into a bit-mapped image. This image is compressed and transmitted along the telephone network to a destination fax machine. This machine decompresses the image and reconstructs the bit-mapped image. A thermal printer usually prints the document.
Radio is the transmission and detection of sound using electromagnetic waves that travel through the air. When a radio receiver is tuned to the frequency of a radio station, a signal is received. Radio remains a popular means of communication. It allows people to receive up-to-date information and entertainment. This form of radio is restricted to a one-way transmission of data. Radio can also be used as a two-way medium where telephones are not a feasible option (such as in emergency service vehicles).
Television is the transmission and detection of images and sound using electromagnetic waves that travel through the air. A scene to be televised is translated into a sequence of electrical pulses that are transmitted via an antenna. The television translates the electrical pulses into a corresponding sequence of images and sounds that are displayed via the screen and speakers.