In telephony, beep lines [lower-alpha 1] were improvised conference calls hosted over busy signals, loop-around test tones, or certain automated informational service numbers, active in the United States from the early 1950s to the mid-1980s. [5] [6] [7] [1] [3] These lines allowed callers to communicate with up to dozens of other people simultaneously, the conversations often punctuated by the busy tone "beep" and accompanying intercept message. Such lines were a consequence of the electromechanical nature of switching equipment within the central offices of the public switched telephone network in widespread use at the time. Some journalists have perceived beep lines as an early form of social media. [8] [9]
For most of the 20th century, calls were usually placed on the public switched telephone network via electromechanical switching equipment. When a caller dialed a number that was busy or permanently unavailable, the central office of their carrier would shunt the incoming call to a circuit on which the busy signal tone was produced. These busy signal circuits did not have their voice path cut off, and as a result, if two or more people reached the same busy signal, they could potentially talk to each other and host a conversation over the sound of the busy signal. [10] [2] [3] The majority of participants were teenagers using these lines to hold informal conversations with strangers in their locality, as well as to collect the phone numbers of potential dates and friends. [10] [1] [11] Beep lines were also a popular spot for phone phreaks, or people who deliberately experimented with and explored public telephone networks, during the 1970s. [6] : C1
This phenomenon of impromptu conference calls was known among telephone company workers as early as the early 1950s and was first publicized by the International News Service reporter Emily Belser in 1953. [12] [13] In 1961, The Idaho Statesman gave the phenomenon a name: "moondialing". [5] As central offices did not send answer supervision to busy signals, conversations hosted over these so-called "beep lines" were toll-free in most cases. [3]
A common point of discovery for the beep line back in the 1950s and 1960s were call-in segments of radio programs. [12] [10] As dozens of callers attempted to reach the DJ or talk show host at the same time, many would invariably reach a busy signal, through which they could speak to other shunted callers. [10] [14] [8] : 3–2 Another entry point was permanently unavailable numbers or loop-around test numbers intended for internal use by the telephone company. [15] [16] [6] : C1 Such numbers were often spread by word of mouth or published in local teen-oriented weeklies. [17] [16] [10] Beep lines proved infectiously popular in the 1960s and 1970s; for example, New England Telephone in 1963 reporting a sharp uptick in busy signal calls in one week (from 1,495 to 27,928) after a beep line number was published in a teen weekly, according to Time magazine. [10]
The pace of conversations hosted over the beep line was often choppy and monosyllabic if the machinery generating the busy tone was particularly loud. [18] [15] The number of concurrent callers on beep lines at any given time could number between 30 and 40 or potentially more. [19] : 1 While beep lines were not initially illegal in the United States, [16] [lower-alpha 2] they were frowned upon by the telephone companies because of their potential to overload a main trunk line in a central office, [4] preventing normal telephone service for a given area and potentially leading to outages for critical lines such as hospitals and emergency services. [19] : 1 [20] Some measures within central offices to quash beep lines included making the busy tone louder or by increasing the interruptions per minute of the tone—to the chagrin of regular callers who found these new tones obnoxious. [19] : 2 Other actions included implementing devices within the electromechanical switching equipment, such as resistors, to inhibit the voice path; [5] rerouting the busy signals or loop-around numbers; [21] or by upgrading the central office equipment to electronic switching systems (ESS). [22] [23] [15] These measures were expensive to implement at the time and were often to no avail, [5] [13] as beep line enthusiasts would cycle through secretive beep lines or connect to distant exchanges with older electromechanical switching equipment and talk there. [24] [15]
Beep lines continued into the 1980s in some rural areas but mostly vanished by the mid-1980s as the vast majority of central offices completed the conversion of their equipment to electronic switching systems. [25] [1]
Dual-tone multi-frequency signaling (DTMF) is a telecommunication signaling system using the voice-frequency band over telephone lines between telephone equipment and other communications devices and switching centers. DTMF was first developed in the Bell System in the United States, and became known under the trademark Touch-Tone for use in push-button telephones supplied to telephone customers, starting in 1963. DTMF is standardized as ITU-T Recommendation Q.23. It is also known in the UK as MF4.
Telephony is the field of technology involving the development, application, and deployment of telecommunications 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.
Phreaking is a slang term coined to describe the activity of a culture of people who study, experiment with, or explore telecommunication systems, such as equipment and systems connected to public telephone networks. The term phreak is a sensational spelling of the word freak with the ph- from phone, and may also refer to the use of various audio frequencies to manipulate a phone system. Phreak, phreaker, or phone phreak are names used for and by individuals who participate in phreaking.
Plain Old Telephone Service (POTS), or Plain Ordinary Telephone System, is a retronym for voice-grade telephone service that employs analog signal transmission over copper loops. The term POTS originally stood for Post Office Telephone Service, as early telephone lines in many regions were operated directly by local Post Offices. For instance, in New Zealand, the telephone system remained under Post Office control until the 1980s.
A dial tone is a telephony signal sent by a telephone exchange or private branch exchange (PBX) to a terminating device, such as a telephone, when an off-hook condition is detected. It indicates that the exchange is working and is ready to initiate a telephone call. The tone stops when the first dialed digit is recognized. If no digits are forthcoming, the partial dial procedure is invoked, often eliciting a special information tone and an intercept message, followed by the off-hook tone, requiring the caller to hang up and redial.
A blue box is an electronic device that produces tones used to generate the in-band signaling tones formerly used within the North American long-distance telephone network to send line status and called number information over voice circuits. During that period, charges associated with long-distance calling were commonplace and could be significant, depending on the time, duration and destination of the call. A blue box device allowed for circumventing these charges by enabling an illicit user, referred to as a "phreaker," to place long-distance calls, without using the network's user facilities, that would be billed to another number or dismissed entirely by the telecom company's billing system as an incomplete call. A number of similar "color boxes" were also created to control other aspects of the phone network.
An answering machine, answerphone, or message machine, also known as telephone messaging machine in the UK and some Commonwealth countries, ansaphone or ansafone, or telephone answering device (TAD), is used for answering telephone calls and recording callers' messages.
A voicemail system is a computer-based system that allows callers to leave a recorded message when the recipient has been unable or unwilling to answer the phone. Calls may be diverted to voicemail manually or automatically. The caller is prompted to leave a message and the recipient can retrieve the message at a later time.
A busy signal in telephony is an audible call-progress tone or audible signal to the calling party that indicates failure to complete the requested connection of that particular telephone call.
A telephone call or telephone conversation, also known as a phone call or voice call, is a connection over a telephone network between the called party and the calling party. Telephone calls started in the late 19th century. As technology has improved, a majority of telephone calls are made over a cellular network through mobile phones or over the internet with Voice over IP. Telephone calls are typically used for real-time conversation between two or more parties, especially when the parties cannot meet in person.
Call waiting is a telephone service where a subscriber can accept a second incoming telephone call by placing an in-progress call on hold—and may also switch between calls. With some providers it can be combined with additional features such as conferencing, call forwarding, and caller ID. Call waiting is intended to alleviate the need to have more than one telephone line or number for voice communications.
In telephony, multi-frequency signaling (MF) is a type of signaling that was introduced by the Bell System after World War II. It uses a combination of audible tones for address transport and supervision signaling on trunk lines between central offices. The signaling is sent in-band over the same channel as the bearer channel used for voice traffic.
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.
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).
In telephony, call progress tones are audible tones that provide an indication of the status of a telephone call to the user. The tones are generated by a central office or a private branch exchange (PBX) to the calling party.
Ringing tone is a signaling tone in telecommunication that is heard by the originator of a telephone call while the destination terminal is alerting the receiving party. The tone is typically a repeated cadence similar to a traditional power ringing signal (ringtone), but is usually not played synchronously. Various telecommunication groups, such as the Bell System and the General Post Office (GPO) developed standards, in part taken over by the European Telecommunications Standards Institute (ETSI) and other standards bodies. With modern cell phone and smartphone technology ringing tone can be customized and even used for advertising.
A telephone number is a sequence of digits assigned to a landline telephone subscriber station connected to a telephone line or to a wireless electronic telephony device, such as a radio telephone or a mobile telephone, or to other devices for data transmission via the public switched telephone network (PSTN), or other public and private networks. Modern smart phones have added a built-in layer of abstraction whereby individuals or businesses are saved into a contacts application and the numbers no longer have to be written down or memorized.
Ringing is a telecommunication signal that causes a bell or other device to alert a telephone subscriber to an incoming telephone call. Historically, this entailed sending a high-voltage alternating current over the telephone line to a customer station which contained an electromagnetic bell. It is therefore also commonly referred to as power ringing, to distinguish it from another signal, audible ringing, or ringing tone, which is sent to the originating caller to indicate that the destination telephone is in fact ringing.
A telephone exchange, also known as a telephone switch or central office, is a crucial component in the public switched telephone network (PSTN) or large enterprise telecommunications systems. It facilitates the interconnection of telephone subscriber lines or digital system virtual circuits, enabling telephone calls between subscribers.
The Panel Machine Switching System is a type of automatic telephone exchange for urban service that was used in the Bell System in the United States for seven decades. The first semi-mechanical types of this design were installed in 1915 in Newark, New Jersey, and the last were retired in the same city in 1983.