Plain old telephone service (POTS), or rarely publicly offered telephone service, is a retronym for voice-grade telephone service that employs analog signal transmission over copper loops.
POTS was the standard service offering from telephone companies in the United States until c. 1988, when the Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI) was introduced, followed by the development of cellular telephone systems and voice over internet protocol (VoIP).
A landline, or fixed line, is telephone service provided to a subscriber via cable or wire, i.e. metal conductors or optical fiber. The term differentiates a telephone service from the now ubiquitous wireless service. A landline allows multiple telephones sets to be connected simultaneously to the same line, and is loosely described as plain old telephone service (POTS).
Landline services are traditionally provided via the outside plant of a telephone company, consisting of analogue copper wire originating from a telephone company's central office, or wirencenter. Landline service often includes services that use Internet Protocol via broadband services.
In telecommunications, broadband or high speed is the wide-bandwidth data transmission that uses signals at a wide spread of frequencies or several different simultaneous frequencies. It is used in fast Internet access where the transmission medium can be coaxial cable, optical fiber, wireless Internet (radio), twisted pair cable, or satellite.
Originally used to mean "using a wide-spread frequency" and for services that were analog at the lowest level, in the context of Internet access, "broadband" is now often used to mean any high-speed Internet access that is seemingly always "on" and is faster than dial-up access over traditional analog or ISDN PSTN services.
Voice over Internet Protocol (VoIP), also known as IP telephony, is a set of technologies used primarily for voice communication sessions over Internet Protocol (IP) networks, such as the Internet. VoIP enables voice calls to be transmitted as data packets, facilitating various methods of voice communication, including traditional applications like Skype, Microsoft Teams, Google Voice, and VoIP phones. Regular telephones can also be used for VoIP by connecting them to the Internet via analog telephone adapters (ATAs), which convert traditional telephone signals into digital data packets that can be transmitted over IP networks.
The broader terms Internet telephony, broadband telephony, and broadband phone service specifically refer to the delivery of voice and other communication services, such as fax, SMS, and voice messaging, over the Internet, in contrast to the traditional public switched telephone network (PSTN), commonly known as plain old telephone service (POTS).
Videotelephony (also known as videoconferencing or video calling or telepresense) is the use of audio and video for simultaneous two-way communication. Today, videotelephony is widespread. There are many terms to refer to videotelephony. Videophones are standalone devices for video calling (compare Telephone). In the present day, devices like smartphones and computers are capable of video calling, reducing the demand for separate videophones. Videoconferencing implies group communication. Videoconferencing is used in telepresence, whose goal is to create the illusion that remote participants are in the same room.
The concept of videotelephony was conceived in the late 19th century, and versions were demonstrated to the public starting in the 1930s. In April, 1930, reporters gathered at AT&T corporate headquarters on Broadway in New York City for the first public demonstration of two-way video telephony. The event linked the headquarters building with a Bell laboratories building on West Street.Early demonstrations were installed at booths in post offices and shown at various world expositions. AT&T demonstrated Picturephone at the 1964 World’s Fair in New York City. In 1970, AT&T launched Picturephone as the first commercial personal videotelephone system. In addition to videophones, there existed image phones which exchanged still images between units every few seconds over conventional telephone lines. The development of advanced video codecs, more powerful CPUs, and high-bandwidth Internet service in the late 1990s allowed digital videophones to provide high-quality low-cost color service between users almost any place in the world.