Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Work on the standard began in 1980 at Bell Labs and was formally standardized in 1988 in the CCITT "Red Book". By the time the standard was released, newer networking systems with much greater speeds were available, and ISDN saw relatively little uptake in the wider market. One estimate suggests ISDN use peaked at a worldwide total of 25 million subscribers at a time when 1.3 billion analog lines were in use. ISDN has largely been replaced with digital subscriber line (DSL) systems of much higher performance.
A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into electronic signals that are transmitted via cables and other communication channels to another telephone which reproduces the sound to the receiving user. The term is derived from Greek: τῆλε and φωνή, together meaning distant voice. A common short form of the term is phone, which came into use early in the telephone's history.
Title 47 CFR Part 68 is a section of the Code of Federal Regulations of the United States that regulate the direct electrical connection of telecommunications equipment and customer premises wiring with the public switched telephone network, certain private line services, and connection of private branch exchange (PBX) equipment to certain telecommunication interfaces.
Telephony is the field of technology involving the development, application, and deployment of telecommunication services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is intimately linked to the invention and development of the telephone.
Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for voice calls for the delivery of voice communication sessions over Internet Protocol (IP) networks, such as the Internet.
Plain Old Telephone Service (POTS), or Plain Ordinary Telephone System, is a retronym for voice-grade telephone service employing analog signal transmission over copper loops. Originally POTS stood for Post Office Telephone Service as early phone lines in most parts of the world were operated directly by the local Post Office.
A voicemail system is a computer-based system that allows people to leave a recorded message when the recipient is unable to answer the phone. The caller is prompted to leave a message and the recipient can retrieve said message at a later time.
The public switched telephone network (PSTN) is the aggregate of the world's telephone networks that are operated by national, regional, or local telephony operators. It provides infrastructure and services for public telephony. The PSTN consists of telephone lines, fiber-optic cables, microwave transmission links, cellular networks, communications satellites, and undersea telephone cables interconnected by switching centers, such as central offices, network tandems, and international gateways, which allow telephone users to communicate with each other.
The director telephone system was a development of the Strowger or step-by-step (SXS) switching system used in London and five other large cities in the UK from the 1920s to the 1980s.
Phone fraud, or more generally communications fraud, is the use of telecommunications products or services with the intention of illegally acquiring money from, or failing to pay, a telecommunication company or its customers.
Asterisk is a software implementation of a private branch exchange (PBX). In conjunction with suitable telephony hardware interfaces and network applications, Asterisk is used to establish and control telephone calls between telecommunication endpoints such as customary telephone sets, destinations on the public switched telephone network (PSTN) and devices or services on voice over Internet Protocol (VoIP) networks. Its name comes from the asterisk (*) symbol for a signal used in dual-tone multi-frequency (DTMF) dialing.
A business telephone system is a telephone system typically used in business environments, encompassing the range of technology from the key telephone system (KTS) to the private branch exchange (PBX).
On analog telephone lines with special services, a flash or register-recall signal is used to control functions on the public telephone exchange, PBX or VoIP ATA.
Nortel Meridian is a private branch exchange telephone switching system. It provides advanced voice features, data connectivity, LAN communications, computer telephony integration (CTI), and information services for communication applications ranging from 60 to 80,000 lines.
In residential telephony, an extension telephone is an additional telephone wired to the same telephone line as another. In middle 20th century telephone jargon, the first telephone on a line was a "Main Station" and subsequent ones "Extensions" or even called as intercom. Such extension phones allow making or receiving calls in different rooms, for example in a home, but any incoming call would ring all extensions and any one extension being in use would cause the line to be busy for all users. Some telephones intended for use as extensions have built in intercom features; a key telephone system for a small business may offer two to five lines, lamps indicating lines already in use, the ability to place calls on 'hold' and an intercom on each of the multiple extensions.
Unified communications (UC) is a business and marketing concept describing the integration of enterprise communication services such as instant messaging (chat), presence information, voice, mobility features, audio, web & video conferencing, fixed-mobile convergence (FMC), desktop sharing, data sharing, call control and speech recognition with non-real-time communication services such as unified messaging. UC is not necessarily a single product, but a set of products that provides a consistent unified user interface and user experience across multiple devices and media types.
UNIStim is a deprecated Telecommunications protocol developed by Nortel for IP Phone and IP PBX communications.
CT Connect is a software product that allows computer applications to monitor and control telephone calls. This monitoring and control is called computer-telephone integration, or CTI. CT Connect implements CTI by providing server software that supports the CTI link protocols used by a range of telephone systems, and client software that provides an application programming interface (API) for telephony functions.
Cloud communications are Internet-based voice and data communications where telecommunications applications, switching and storage are hosted by a third-party outside of the organization using them, and they are accessed over the public Internet. Cloud services is a broad term, referring primarily to data-center-hosted services that are run and accessed over an Internet infrastructure. Until recently, these services have been data-centric, but with the evolution of VoIP, voice has become part of the cloud phenomenon. Cloud telephony refers specifically to voice services and more specifically the replacement of conventional business telephone equipment, such as a private branch exchange (PBX), with third-party VoIP service.
