The Carterfone is a device invented by Thomas Carter. It connects a two-way radio system to the telephone system, allowing someone on the radio to talk to someone on the phone. This makes it a direct predecessor to today's autopatch. The connection is acoustic -- sound travels through the air between the Carterfone and a conventional telephone that is part of the telephone system.
The reason the Carterfone connected the telephone and radio acoustically, instead of electrically, is that telephone network owners were legally allowed to and did bar devices they did not own from being connected electrically to their networks.
The Carterfone decision (13 F.C.C.2d 420) was a landmark United States regulatory decision that opened the public switched telephone network (PSTN) in America to customer-premises equipment (CPE). Twelve years earlier, a court had ruled in the Hush-A-Phone case that devices could mechanically connect to the telephone system (such as a rubber cup attached to a phone-company-owned telephone) without the permission of AT&T. In 1968, the Federal Communications Commission (FCC) extended this privilege by allowing the Carterfone and other devices to be connected electrically to the AT&T network, as long as they did not cause harm to the system.
The device is acoustically, but not electrically, connected to the public switched telephone network. [1] It was electrically connected to the base station of the mobile radio system, and got its power from the base station. [1] : 659 All electrical parts were encased in bakelite, an early plastic.
When someone on a two-way radio wished to speak to someone on phone, or "landline" (e.g., "Central dispatch, patch me through to McGarrett"), the station operator at the base would dial the telephone number. When callers on the radio and on the telephone were both in contact with the base station operator, the handset of the operator's telephone was placed on a cradle built into the Carterfone device. A voice-operated switch in the Carterfone automatically switched on the radio transmitter when the telephone caller was speaking; when they stopped speaking, the radio returned to a receiving condition. A separate speaker was attached to the Carterfone to allow the base station operator to monitor the conversation, adjust the voice volume, and hang up their telephone when the conversation had ended. [2]
This particular device was involved in a landmark United States regulatory decision related to telecommunications. In a twelve-year prior decision from 1956, a court had ruled in the Hush-A-Phone case that devices could mechanically connect to the telephone system (such as a rubber cup attached to a phone-company-owned telephone) without the permission of AT&T. In 1968, the Federal Communications Commission extended this privilege by allowing the Carterfone and other devices to be connected electrically to the AT&T network, as long as they did not cause harm to the system. This ruling, commonly called "the Carterfone decision" (13 F.C.C.2d 420), created the possibility of selling devices that could connect to the phone system using a protective coupler and opened the market to customer-premises equipment. The decision is often referred to as "any lawful device", allowing later innovations like answering machines, fax machines, and modems (which initially used the same type of manual acoustic coupler as the Carterfone) to proliferate.
In February 2007, a petition for rulemaking was filed with the FCC by Skype, requesting the FCC to apply the Carterfone regulations to the wireless industry—which would mean that OEMs, portals and others will be able to offer wireless devices and services without the cellular operators needing to approve the handsets. However, on April 1, 2008, FCC chairman Kevin Martin indicated that he would oppose Skype's request. [3] On April 17, 2015, this petition for rulemaking was dismissed without prejudice by the FCC at the request of Skype's current owner, Microsoft Corporation. [4]
A telephone, colloquially referred to as a phone, is a telecommunications device that enables 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 Ancient Greek: τῆλε, romanized: tēle, lit. 'far' and φωνή, together meaning distant voice.
In telecommunications, an acoustic coupler is an interface device for coupling electrical signals by acoustical means—usually into and out of a telephone.
In telecommunications, a customer-premises equipment or customer-provided equipment (CPE) is any terminal and associated equipment located at a subscriber's premises and connected with a carrier's telecommunication circuit at the demarcation point ("demarc"). The demarc is a point established in a building or complex to separate customer equipment from the equipment located in either the distribution infrastructure or central office of the communications service provider.
The term data access arrangement (DAA) has the following meanings:
In radio communication, a transceiver is an electronic device which is a combination of a radio transmitter and a receiver, hence the name. It can both transmit and receive radio waves using an antenna, for communication purposes. These two related functions are often combined in a single device to reduce manufacturing costs. The term is also used for other devices which can both transmit and receive through a communications channel, such as optical transceivers which transmit and receive light in optical fiber systems, and bus transceivers which transmit and receive digital data in computer data buses.
Voice over Internet Protocol (VoIP), also known as IP telephony, refers to a set of technologies used 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.
Enhanced 911 is a system used in North America to automatically provide the caller's location to 911 dispatchers. 911 is the universal emergency telephone number in the region. In the European Union, a similar system exists known as E112 and known as eCall when called by a vehicle.
In telephony, the demarcation point is the point at which the public switched telephone network ends and connects with the customer's on-premises wiring. It is the dividing line which determines who is responsible for installation and maintenance of wiring and equipment—customer/subscriber, or telephone company/provider. The demarcation point varies between countries and has changed over time.
A cordless telephone or portable telephone has a portable telephone handset that connects by radio to a base station connected to the public telephone network. The operational range is limited, usually to the same building or within some short distance from the base station.
In analog telephony, a telephone hybrid is the component at the ends of a subscriber line of the public switched telephone network (PSTN) that converts between two-wire and four-wire forms of bidirectional audio paths. When used in broadcast facilities to enable the airing of telephone callers, the broadcast-quality telephone hybrid is known as a broadcast telephone hybrid or telephone balance unit.
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).
Mobile telephony is the provision of wireless telephone services to mobile phones, distinguishing it from fixed-location telephony provided via landline phones. Traditionally, telephony specifically refers to voice communication, though the distinction has become less clear with the integration of additional features such as text messaging and data services.
Mobile radio telephone systems were mobile telephony systems that preceded modern cellular network technology. Since they were the predecessors of the first generation of cellular telephones, these systems are sometimes retroactively referred to as pre-cellular systems. Technologies used in pre-cellular systems included the Push-to-talk, Mobile Telephone Service (MTS), Improved Mobile Telephone Service (IMTS), and Advanced Mobile Telephone System (AMTS) systems. These early mobile telephone systems can be distinguished from earlier closed radiotelephone systems in that they were available as a commercial service that was part of the public switched telephone network, with their own telephone numbers, rather than part of a closed network such as a police radio or taxi dispatching system.
The history of mobile phones covers mobile communication devices that connect wirelessly to the public switched telephone network.
In telecommunications, interconnection is the physical linking of a carrier's network with equipment or facilities not belonging to that network. The term may refer to a connection between a carrier's facilities and the equipment belonging to its customer, or to a connection between two or more carriers.
Hush-A-Phone v. United States, 238 F.2d 266 was a seminal ruling in United States telecommunications decided by the D.C. Circuit Court of Appeals. Hush-A-Phone Corporation marketed a small, cup-like device which mounted on the speaking party's microphone, reducing the risk of conversations being overheard and increasing sound fidelity for the listening party. At the time, AT&T had a near-monopoly on America's phone system, even controlling the equipment attached to its network. In this era, Americans had to lease equipment from "Ma Bell" or use approved devices. At this time Hush-A-Phone had been around for 20 years without any issues. However, when an AT&T lawyer saw one in a store window, the company decided to sue on the grounds that anything attached to a phone could damage their network.
The Hush-A-Phone was a device designed to attach to the transmitter of a telephone to reduce noise pollution and increase privacy. Sold by the Hush-A-Phone company, the device was frequently described in its commercial advertisements as "a voice silencer designed for confidential conversation, clear transmission and office quiet. Not a permanent attachment. Slips right on and off the mouthpiece of any phone".
CT2 is a cordless telephony standard that was used in the early 1990s to provide short-range proto-mobile phone service in some countries in Europe and in Hong Kong. It is considered the precursor to the more successful DECT system. CT2 was also referred to by its marketing name, Telepoint.
A modulator-demodulator, commonly referred to as a 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 LEDs to radio.
United States v. AT&T, 552 F.Supp. 131 (1982), was a ruling of the United States District Court for the District of Columbia, that led to the 1984 Bell System divestiture, and the breakup of the old AT&T natural monopoly into seven regional Bell operating companies and a much smaller new version of AT&T.