DSS stands for Decision Support System. Data are considered on-line if they can be accessed and manipulated by the computer. When all the transactions are grouped together for processing, this is an example of on-line processing. The integration of computer systems, terminals, and communication links is called a computer network. Virtually all computers and hardware devices are located within a typical data communications network is located in a single room, called the machine room.
Fax machines transfer hard-copy images via telephone lines.
The collection and distribution of the electronic information from and to remote facilities is referred to as data communications. The function of a multiplexer is to concentrate the signals of several low speed devices over a single high-speed line to the host computer. The device that converts electrical digital signals so that they can be transmitted over regular telephone lines is a modem. Modems convert computer electrical digital signals to analog signals, but not analog signals to digital signals. Modems are needed to transmit data over telephone lines.