Telephone network in the context of "Dial-up Internet access"

Information and communications technology (ICT) is an extensional term for information technology (IT) that stresses the role of unified communications and the integration of telecommunications (telephone lines and wireless signals) and computers, as well as necessary enterprise software, middleware, storage and audiovisual, that enable users to access, store, transmit, understand and manipulate information.

ICT is also used to refer to the convergence of audiovisuals and telephone networks with computer networks through a single cabling or link system. There are large economic incentives to merge the telephone networks with the computer network system using a single unified system of cabling, signal distribution, and management. ICT is an umbrella term that includes any communication device, encompassing radio, television, cell phones, computer and network hardware, satellite systems and so on, as well as the various services and appliances with them such as video conferencing and distance learning. ICT also includes analog technology, such as paper communication, and any mode that transmits communication.

A telephone number is the address of a telecommunication endpoint, such as a telephone, in a telephone network, such as the public switched telephone network (PSTN). A telephone number typically consists of a sequence of digits, but historically letters were also used in connection with telephone exchange names.

Telephone numbers facilitate the switching and routing of calls using a system of destination code routing. Telephone numbers are entered or dialed by a calling party on the originating telephone set, which transmits the sequence of digits in the process of signaling to a telephone exchange. The exchange completes the call either to another locally connected subscriber or via the PSTN to the called party. Telephone numbers are assigned within the framework of a national or regional telephone numbering plan to subscribers by telephone service operators, which may be commercial entities, state-controlled administrations, or other telecommunication industry associations.

Automation describes a wide range of technologies that reduce human intervention in processes, mainly by predetermining decision criteria, subprocess relationships, and related actions, as well as embodying those predeterminations in machines. Automation has been achieved by various means including mechanical, hydraulic, pneumatic, electrical, electronic devices, and computers, usually in combination. Complicated systems, such as modern factories, airplanes, and ships typically use combinations of all of these techniques. The benefits of automation includes labor savings, reducing waste, savings in electricity costs, savings in material costs, and improvements to quality, accuracy, and precision.

Automation includes the use of various equipment and control systems such as machinery, processes in factories, boilers, and heat-treating ovens, switching on telephone networks, steering, stabilization of ships, aircraft and other applications and vehicles with reduced human intervention. Examples range from a household thermostat controlling a boiler to a large industrial control system with tens of thousands of input measurements and output control signals. Automation has also found a home in the banking industry. It can range from simple on-off control to multi-variable high-level algorithms in terms of control complexity.

A telephone call, phone call, voice call, or simply a call, is the use of a connection over a telephone network between two parties for audio communication. To start a call, the calling party, the caller, opens a connection for a particular phone number and waits for an answer to the request; often indicated by an audible ringtone. To answer the call, the called party accepts the request to start a conversation. A party is most commonly a single person, but can be a group of people (i.e. conference call) or a machine (i.e. fax). In some contexts, the term A-Number refers to the caller and B-Number refers to the called party.

The telephone call was enabled by multiple inventions in the mid- to late-19th century including the telephone. Initial technology involved point-to-point electrical wire connections between telephone installations, until centralized exchanges evolved where telephone operators established each interconnection manually at a telephone switchboard after asking the calling party for their call destination. After the invention of automatic telephone exchanges in the 1890s, the process became increasingly automated, eventually leading to the widespread adoption of digital exchanges in the second half of the 20th century, including the transition to wireless communication via mobile telephone networks and cellular networks. With the development of the Internet, the cost of telephone calls was drastically reduced with Voice over Internet Protocol (VoIP).

Teletraffic engineering, or telecommunications traffic engineering is the application of transportation traffic engineering theory to telecommunications. Teletraffic engineers use their knowledge of statistics including queuing theory, the nature of traffic, their practical models, their measurements and simulations to make predictions and to plan telecommunication networks such as a telephone network or the Internet. These tools and knowledge help provide reliable service at lower cost.

The field was created by the work of A. K. Erlang for circuit-switched networks but is applicable to packet-switched networks, as they both exhibit Markovian properties, and can hence be modeled by e.g. a Poisson arrival process.