This article is about shared service telephone lines. For dating party lines, see Chat line. For conference calls spoken over busy signals or test numbers, see Beep line.
A party line (multiparty line, shared service line, party wire) is a local looptelephone circuit that is shared by multiple telephone service subscribers.[1][2][3]
Party line systems were widely used to provide telephone service, starting with the first commercial switchboards in 1878.[4] A majority of Bell System subscribers in the mid-20th century in the United States and Canada were served by party lines, which had a discount over individual service. During wartime shortages, these were often the only available lines.
British users similarly benefited from the party line discount. Farmers in rural Australia and South Africa used party lines, where a single line spanned miles from the nearest town to one property and on to the next.[5][6]
History
Circuit diagram, 1905
Telephone companies offered party lines beginning in the late 1800s,[7] although subscribers in all but the most rural areas may have had the option to upgrade to individual line service at an additional monthly charge. The service was common in sparsely populated areas where subscribers were spread across large distances. An example is Australia where these were operated by the Government Postmaster General's Department. In rural areas in the early 20th century, additional subscribers and telephones, often numbering several dozen, were frequently connected to the single loop available.
Party lines provided no privacy in communication. They were frequently used as a source of entertainment and gossip, as well as a means of quickly alerting entire neighbourhoods of emergencies such as fires,[8] becoming a cultural fixture of rural areas for many decades.
The rapid growth of telephone service demand, especially after WWII, resulted in many party line installations in the middle of the 20th century in the United States. This often led to traffic congestion in the telephone network, as the line to a destination telephone was often busy.[9] Nearly three-quarters of Pennsylvania residential service in 1943 was party line, with users encouraged to limit calls to five minutes.[10] Shortages persisted for years after each war; individual lines in Montreal remained in short supply at the end of 1919[11] and similar shortages were reported by telephone companies in Florida as late as 1948.[12][13] Some rural users had to run their own wires to reach the utility's lines.[14]
1959 rates for telephone lines in Indiana. Subscribers in town could choose an individual line or a line shared by two or four parties. All rural lines were party lines shared with several neighbors.
Objections about one party monopolizing a multi-party line were a staple of complaints to telephone companies and letters to advice columnists for years[15] and eavesdropping on calls remained an ongoing concern.[16]
In December 1942, University of Tennessee's strategy in an American football game versus University of Mississippi was revealed to the opposing coach, when a telephone on the Ole Miss team's bench had been inadvertently wired to the same party line.[17] In May 1952, an alleged bookmaking operation in St. Petersburg, Florida was shut down after one month of operation in a rented storefront using a party-line telephone.[18] In June 1968, the conviction of three Winter Park, Florida men on bookmaking charges was overturned as police had used a party-line telephone in a rented house on the same line as the suspects to unlawfully intercept their communications.[19]
In 1956, Southern Bell officials refused a request from a public utilities commissioner in Jackson, Mississippi to segregate party telephone lines on racial boundaries.[20]
While primitive lockout devices to prevent two subscribers from picking up the same line at the same time were proposed relatively early,[21] multiple simultaneous calls did not become viable until the initial tests of transistorisedpair gain devices in 1955.[22][23] Any handset off-hook therefore tied up the line for everyone.
Many jurisdictions require a person engaged in a call on a party line to end the call immediately if another party needs the line for an emergency. Such laws also provide penalties for abuse by falsifying emergency situations. In May 1955, a Rhinebeck, New York woman was indicted by a grand jury after her refusal to relinquish a party line delayed a volunteer firefighter's effort to report a grass fire. The fire destroyed a shed and a barn.[24][25] She was given a suspended sentence.[26] In June 1970, a sixteen-year-old girl and a woman were charged after refusing to relinquish a party line to allow a distress call as three boys drowned in a pond in Walsenburg, Colorado.[27][28][29][30][31]
Decommissioning
By the late 1980s, party lines were removed in most locales. They were not supported by new technologies and subscriber-owned equipment such as answering machines and computermodems. Meanwhile, the electro-mechanical switching equipment required for their operation was rapidly becoming obsolete, supplanted by electronic and digital switching equipment. The new telephone exchange equipment offered vertical service code calling features such as call forwarding and call waiting, but often was incompatible with multi-party lines. Party lines in the United States were ineligible for Universal Service Fund subsidies, leading telephone companies to convert them to individual lines to benefit from these subsidies.
One of the last manual telephone exchanges with party lines in Australia was closed down in 1986 in the township of Collarenebri, where most town residents had a telephone number of only three digits. To make a call outside the exchange area it was necessary to call the exchange to place a call. For rural residents, many were on a single telephone line identified by a number and a property name, such as "Gundabluie 1". Each party on that single line was identified by a letter, and the ringing pattern for that party would consist of the corresponding letter in Morse code. This distinctive ring would alert all parties on the line who the call was for.
Pacific Bell phased out most of its party lines by 1997, and the last ones operating in Nevada shut down in 2001. As of 2002, SBC Ameritech's only operating party lines were located in Michigan.[37][needs update]USA Today reported in 2000 that over 5,000 party lines still existed in the United States, but the majority of them were only connected to one telephone, and therefore appeared like individual telephone service at cheaper rates.[38]
Selective ringing
To signal specific subscribers on party lines selectively, telephone operating companies implemented various signaling systems.
As upgrades made party lines more popular in the 1940s, local telephone companies ran frequent ads to instill community spirit and personal courtesy in party-line subscribers.
The earliest selective system was the code ringing system, in which each telephone subscriber was assigned a specific ringing cadence, (not to be confused with modern ring tones).
Although various systems were implemented, one that limited the number of coded rings but established a uniform and readily understood format, was to first give the subscriber number as individual digits, which could be from one to four digits long per exchange,[39] separated by the instructional word "ring" followed by the two digits of the ring code where the first digit indicated the number of long rings, followed by the second digit indicating the number of short rings. Thus spoken, for example, as "nine, three; ring two, two" to mean subscriber No. 93 with ringing code 2 long and 2 short, and written as "93R22", (and if outside the given exchange, then the exchange would be asked for by name before the requested number and ringing code, e.g. "Rockridge nine, three; ring one, two" i.e. "(On the) Rockridge (exchange), (subscriber No.) nine, three; ring one long, and two short," and written as “Rockridge 93R12”. (The two examples cited in this paragraph are taken directly from usage in the 1935 American film Party Wire.)[40] Whilst this practice was common, it was not ubiquitous, since despite giving a standard configuration for terse, easily interpreted numbers with their respective ring codes, its chief functional drawback was with the first ring always being long and the second always being short, which limited the number of brief and thus practical ringing combinations that could be used on single multiparty subscriber numbers.
Further to this functional deficiency, was a twofold practical deficiency. For though one was only to answer one's own ringing code, every party on the same subscriber line could hear all the ringing codes. This meant firstly, frequently ringing telephones were a disruptive annoyance, as each party on the line had to stop to listen every time the telephone rang to determine if they were the party being called on any given ring.[41] Secondly, if any party on a given line should so be inclined, there was the opportunity to listen to other parties' calls.
More selective ringing methods were introduced using various technologies.
In the system of divided ringing, the ringing circuit was separated from the talking circuit by adding a ground connection between the central office and the subscriber stations for ringing. On the same subscriber line, one party used the tip side of the line and ground for ringing, whilst the other party on the same line used the ring wire and ground for ringing, to achieve full selectivity for two-party lines, in which only the selected station would ring. These names for the wires are derived from the paired cord plugs—used on a manual switchboard—composed of three parts: the tip and the sleeve separated by a narrow metal band called the ring, each of these three components being insulated from one another.[42]
In the Bell System, the two stations were thus called the tip party and the ring party, In combination with code ringing, this method could be extended to four and eight subscribers to reduce the number of disturbances. In several variations of divided ringing, also called grounded ringing, the bells were activated with polarized current, so that full selectivity was achieved for up to four parties.
Another selective ringing system was based on using different ringing frequencies for each station on the party line. In North America, this was used mostly by independent telephone systems, while the Bell System abandoned frequency selective ringing in the early 1900s. Initially four frequencies were used, which were based on a system of harmonic multiples of a frequency of 16+2⁄3Hz. Combined with divided ringing, this provided fully selective service for up to eight stations.
All fully selective ringing systems on party lines still brought the inconvenience of finding the line in use occasionally, by hearing talking when one picked up the phone to make a call. All party lines also required special equipment to complete calls to another party on the same party line.[43]
Characteristics
In the local-battery system of the early cranked magneto phones, the phone's own battery powered its transmitter as well as the receiver of the called phone. If too many phones were off-hook and listening, the additional receivers would load down the transmitter's battery with a voltage so low that no phone could receive an intelligible signal.[citation needed]
With party-line service, particularly if there were more than two subscribers on the line, it was often necessary to complete a long-distance call through the operator to identify and correctly bill the calling party. In some cases, the calling party would misidentify themselves in an attempt to send the bill to another party.[44]
A two-party line split between tip party and ring party could be created in such a way as to allow the central office to determine which party placed an outbound toll call by detecting that one of the ringers was disconnected when that subscriber went off-hook. This system would fail if any provision was made to allow the subscriber to turn off the bells (do not disturb) for privacy or unplug the telephone. It also presumed that each subscriber only had one telephone connected to the line.
One variation of identifying the calling party on direct-dialed long-distance calls is a party code, usually a single digit inside a circle displayed on the phone's number tag. The dialing sequence for such calls is "1" (access number for DDD), the party code, the area code, and the desired number (1 + party code + area code + number).
Systems which identify the caller's name and address to emergency telephone numbers (such as Enhanced 9-1-1 in North America) may be unable to identify which of multiple parties on a shared line placed a distress call; this is aggravated by the use of old mechanical switching equipment for party lines as this obsolete apparatus consistently provides no caller ID and often also lacks automatic number identification capability.
When the party line was already in use, if any of the other subscribers to that line picked up the phone, they could hear and participate in the conversation. Eavesdropping opportunities abounded. If one of the parties used the phone heavily, then the inconvenience for the others was more than occasional, as depicted in the 1959 comedy film Pillow Talk.[45] Dialing one's own number and hanging up would make all phones on the network ring, resulting in the residents on the system (sometimes a half a dozen or more) all answering the phone at the same time. This was sometimes used as a form of prank call, but could also be employed as a form of early warning system for the immediate area, a user could alert all local residents at once. Party lines were typically operated using mechanical switching systems which recognized certain codes for revertive calls; these no longer work on modern electronic or digital switchgear.
Party lines are not suitable for Internet access. If one customer is using dial-up, it will jam the line for all other customers of the same party line. Bridge taps made party lines unsuitable for DSL, even in the few areas where distance from the central office did not already preclude its use. Telephone companies typically do not allow client-owned equipment to be directly connected to party lines, posing an additional obstacle to their use for data.
Barbed wire telephone lines
Barbed wire telephone lines were local networks created in rural America around the turn of the 20th century.[46] In some isolated farming communities, it was not cost-effective for corporations to invest in the telephone infrastructure. Instead, the existing extent of barbed wirefences could be used to transmit electric signals and connect telephones in neighboring farms.
In 1902, The New York Times reported that ranchers in Montana were instituting a telephone exchange in Fort Benton with the goal of eventually connecting every city in the state. The main purpose of such networks was to transmit weather conditions and forecasts, as well as train schedules. [47]
Railroad systems
Telephone service for dispatchers and service personnel between way stations along railways used a form of party line service for many decades starting in the early 1900s. Railroad telephone systems often consisted of several dozen way stations interconnected with a shared line that used DC voltages as high as 400 V for selective signaling to alert called stations.
Carrier systems
With the advent of sophisticated electronics, telephone service providers developed methods to share a single copper line to transmit multiple telephone calls simultaneously. Various pair gain methods using time-division multiplexing and frequency-division multiplexing prevented interference between simultaneous calls. A distant suburb may have a subscriber loop carrier or digital loop carrier system in which a remote concentrator is located near the subscribers to connect multiple local subscriber loops to one common line to a central office exchange. A single optical fibre can also be shared between multiple subscribers in fibre to the cabinet systems.
CATV cable modems are connected to an inherently shared medium. The signal from the shared line is split to multiple subscribers. Signals for television, and data operate at various different carrier frequencies.
Digital wireless connections, such as mobile phones or voice over IP running over rural wireless Internet infrastructure are also inherently a shared medium. Sufficiently high levels of usage of simultaneous active connections cause congestion on a mobile telephone network or impair transmission quality.
Modern usage
Party lines are still in use primarily in rural areas where local loops are long and individual circuits are uneconomical when spread sparsely over a large area. Privacy is limited and congestion often occurs. In isolated communities, party lines have been used for local service only, without the facilities to switch calls through a central office for connection to the public switched telephone network.
An example of a community linked by a party line is in Big Santa Anita Canyon high in the mountains above Los Angeles, near Sierra Madre, California. A group camp, a pack station and 81 cabins all communicate by magneto-type crank phones. One ring is for the pack station, two rings is for the camp and three rings means "all cabins pick up."[48] There are also eight emergency telephone stations located along the hiking trail.[49] The system is a single wire using the ground as a return path. Maintenance of the line was assumed by the association of cabin owners in 2018.[50]
In modern use, the term party line has occasionally been used to market conference calling and voice bulletin board services.
Usage in Popular Culture
Party line telephone service was demonstrated in Season 5, Episode 33 (entitled "Party Line") of the television series Alfred Hitchcock Presents, which aired May 29, 1960 on CBS.
A telephone switchboard was a device used to connect circuits of telephones to establish telephone calls between users or other switchboards, throughout the 20th century. The switchboard was an essential component of a manual telephone exchange, and was operated by switchboard operators who used electrical cords or switches to establish the connections.
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.
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. This allowed 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 as an incomplete call. A number of similar "color boxes" were also created to control other aspects of the phone network.
The North American Numbering Plan (NANP) is a telephone numbering plan for twenty-five regions in twenty countries, primarily in North America and the Caribbean. This group is historically known as World Zone 1 and has the telephone country code 1. Some North American countries, most notably Mexico, do not participate with the NANP.
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.
A toll-free telephone number or freephone number is a telephone number that is billed for all arriving calls. For the calling party, a call to a toll-free number from a landline is free of charge. A toll-free number is identified by a dialing prefix similar to an area code. The specific service access varies by country.
A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, reachable by a system of destination code routing. Telephone numbering plans are defined in each of the administrative regions of the public switched telephone network (PSTN) and in private telephone networks.
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 telephone line or telephone circuit is a single-user circuit on a telephone communication system. It is designed to reproduce speech of a quality that is understandable. It is the physical wire or other signaling medium connecting the user's telephone apparatus to the telecommunications network, and usually also implies a single telephone number for billing purposes reserved for that user. Telephone lines are used to deliver landline telephone service and digital subscriber line (DSL) phone cable service to the premises. Telephone overhead lines are connected to the public switched telephone network. The voltage at a subscriber's network interface is typically 48 V between the ring and tip wires, with tip near ground and ring at –48 V.
In telecommunications, a long-distance call (U.S.) or trunk call is a telephone call made to a location outside a defined local calling area. Long-distance calls are typically charged a higher billing rate than local calls. The term is not necessarily synonymous with placing calls to another telephone area code.
A telephone exchange name or central office name was a distinguishing and memorable name assigned to a central office. It identified the switching system to which a telephone was connected, and facilitated the connection of telephone calls between switching systems in different localities.
The New Zealand telephone numbering plan describes the allocation of telephone numbers in New Zealand and the Pitcairn Islands.
The Number Five Crossbar Switching System is a telephone switch for telephone exchanges designed by Bell Labs and manufactured by Western Electric starting in 1947. It was used in the Bell System principally as a Class 5 telephone switch in the public switched telephone network (PSTN) until the early 1990s, when it was replaced with electronic switching systems. Variants were used as combined Class 4 and Class 5 systems in rural areas, and as a TWX switch.
Tip and ring are the two conductors or sides of a telephone line. Their names are derived from the telephone plugs used for connecting telephone calls in manual switchboards. One side of the line is connected to the metal tip of the plug, and the second is connected to a metal ring behind the tip, separated and insulated from the tip by a non-conducting material. When inserted into a jack, the plug's tip conductor connects first, followed by the ring conductor. In many European countries, tip and ring are referred to as the A and B wires.
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.
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.
The push-button telephone is a telephone that has buttons or keys for dialing a telephone number, in contrast to having a rotary dial as in earlier telephone instruments.
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.
In conventional landline telephony, a non-dialable toll point or toll station was a lone station or line serving a rural subscriber many miles from the nearest central office. As it had no home telephone exchange and therefore no local calling area, no customer could dial its number; all connections to it had to be obtained manually by the long distance operator.
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.
↑ International Correspondence Schools (1916). "Party Line Telephones". Subscribers' Station Equipment. International Library of Technology. Scranton, PA: International Textbook Company. p.20. Retrieved May 27, 2008.
↑ "Pinouts"(PDF). June 3, 2009. Archived from the original(PDF) on May 8, 2018. Retrieved July 24, 2020.
↑ Revertive call circuit, US patent 3461246 filed July 22, 1966 by Schneider Gerhard O K of Stromberg Carlson Corp
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