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.
Digital subscriber line is a family of technologies that are used to transmit digital data over telephone lines. In telecommunications marketing, the term DSL is widely understood to mean asymmetric digital subscriber line (ADSL), the most commonly installed DSL technology, for Internet access.
A symmetric digital subscriber line (SDSL) is a digital subscriber line (DSL) that transmits digital data over the copper wires of the telephone network, where the bandwidth in the downstream direction, from the network to the subscriber, is identical to the bandwidth in the upstream direction, from the subscriber to the network. This symmetric bandwidth can be considered to be the opposite of the asymmetric bandwidth offered by asymmetric digital subscriber line (ADSL) technologies, where the upstream bandwidth is lower than the downstream bandwidth. SDSL is generally marketed at business customers, while ADSL is marketed at private as well as business customers.
A software modem, commonly referred to as a softmodem, is a modem with minimal hardware that uses software running on the host computer, and the computer's resources, in place of the hardware in a conventional modem.
A digital subscriber line access multiplexer is a network device, often located in telephone exchanges, that connects multiple customer digital subscriber line (DSL) interfaces to a high-speed digital communications channel using multiplexing techniques. Its cable internet (DOCSIS) counterpart is the cable modem termination system.
Internet access is a facility or service that provides connectivity for a computer, a computer network, or other network device to the Internet, and for individuals or organizations to access or use applications such as email and the World Wide Web. Internet access is offered for sale by an international hierarchy of Internet service providers (ISPs) using various networking technologies. At the retail level, many organizations, including municipal entities, also provide cost-free access to the general public.
Damn Small Linux (DSL) is a computer operating system for the x86 family of personal computers. It is free and open-source software under the terms of the GNU GPL and other free and open-source licenses. It was designed to run graphical user interface applications on older PC hardware, for example, machines with 486 and early Pentium microprocessors and very little random-access memory (RAM). DSL is a live CD with a size of 50 megabytes (MB). What originally began as an experiment to see how much software could fit in 50 MB eventually became a full Linux distribution. It can be installed on storage media with small capacities, like bootable business cards, USB flash drives, various memory cards, and Zip drives.
Single-pair high-speed digital subscriber line (SHDSL) is a form of symmetric digital subscriber line (SDSL), a data communications technology for equal transmit and receive data rate over copper telephone lines, faster than a conventional voiceband modem can provide. As opposed to other DSL technologies, SHDSL employs trellis-coded pulse-amplitude modulation (TC-PAM). As a baseband transmission scheme, TC-PAM operates at frequencies that include those used by the analog voice plain old telephone service (POTS). As such, a frequency splitter, or DSL filter, cannot be used to allow a telephone line to be shared by both an SHDSL service and a POTS service at the same time. Support of symmetric data rates made SHDSL a popular choice by businesses for private branch exchange (PBX), virtual private network (VPN), web hosting and other data services.
In telephony, pair gain is the transmission of multiple plain old telephone service (POTS) channels over the twisted pair local loop traditionally used for a single subscriber line in telephone systems. Pair gain has the effect of creating additional subscriber lines. This is typically used as an expedient way to solve subscriber line shortages at a location by using existing wiring, instead of installing new wires from the central office to the customer premises. The term was invented in the middle 20th century by analogy with earlier use of gain to extend telephone local loops far from the telephone exchange.
Rate-adaptive digital subscriber line (RADSL) is a pre-standard asymmetric digital subscriber line (ADSL) solution. RADSL was introduced as proprietary technology by AT&T Paradyne, later GlobeSpan Technologies Inc., in June 1996. In September 1999, RADSL technology was formally described by ANSI in T1.TR.59-1999. RADSL supports downstream data rates of up to approximately 8 Mbit/s, upstream data rates up to approximately 1 Mbit/s, and can coexist with POTS voice on the same line.
The Freebox is an ADSL-VDSL-FTTH modem and a set-top box that the French Internet service provider named Free provides to its DSL-FTTH subscribers.
In the field of telecommunications, the concept of triple play service refers to the provision of three essential services — high-speed broadband Internet access, television, and latency-sensitive telephone services — all delivered over a single broadband connection. This approach emphasizes the convergence of multiple services by a single supplier, aiming to enhance user convenience and streamline service delivery.
A digital subscriber line (DSL) modem is a device used to connect a computer or router to a telephone line which provides the digital subscriber line (DSL) service for connection to the Internet, which is often called DSL broadband. The modem connects to a single computer or router, through an Ethernet port, USB port, or is installed in a computer PCI slot.
A dry loop is an unconditioned leased pair of telephone line from a telephone company. The pair does not provide dial tone or battery, as opposed to a wet pair, a line usually without dial tone but with battery.
Etherloop is a hybrid technology combining aspects of Ethernet with other technologies to achieve a result not possible with either technology alone. EtherLoop was originally developed in the 1990s to allow high-speed data communication access to residential customers over standard twisted-pair telephone lines, also known as plain old telephone service or POTS. The technology development effort was begun at Northern Telecom in order to allow telephone companies to compete with the high-speed local data access then beginning to be offered by cable TV providers.
Standalone or Stand-alone may refer to:
Asymmetric digital subscriber line (ADSL) is a type of digital subscriber line (DSL) technology, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide. ADSL differs from the less common symmetric digital subscriber line (SDSL). In ADSL, bandwidth and bit rate are said to be asymmetric, meaning greater toward the customer premises (downstream) than the reverse (upstream). Providers usually market ADSL as an Internet access service primarily for downloading content from the Internet, but not for serving content accessed by others.
A modulator-demodulator or modem is a computer hardware device that converts data from a digital format into a format suitable for an analog transmission medium such as telephone or radio. A modem transmits data by modulating one or more carrier wave signals to encode digital information, while the receiver demodulates the signal to recreate the original digital information. The goal is to produce a signal that can be transmitted easily and decoded reliably. Modems can be used with almost any means of transmitting analog signals, from light-emitting diodes to radio.
John Mathew Cioffi is an American electrical engineer, educator and inventor who has made contributions in telecommunication system theory, specifically in coding theory and information theory. Best known as "the father of DSL," Cioffi's pioneering research was instrumental in making digital subscriber line (DSL) technology practical and has led to over 400 publications and more than 100 pending or issued patents, many of which are licensed.
