Party line (telephony)

[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.

In rural areas in the early 20th century, additional subscribers and telephones, often numbering several dozen, were frequently connected to the single loop available.

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.

[9] Nearly three-quarters of Pennsylvania residential service in 1943 was party line, with users encouraged to limit calls to five minutes.

[14] 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.

[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.

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.

[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.

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.

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.

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.

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.

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 were local networks created in rural America around the turn of the 20th century.

Instead, the existing extent of barbed wire fences could be used to transmit electric signals and connect telephones in neighboring farms.

Such networks could be isolated to allow individual communication[47] but were almost always party lines, and specific recipients were determined by manually generated ringing codes.

[48] 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.

Sufficiently high levels of usage of simultaneous active connections cause congestion on a mobile telephone network or impair transmission quality.

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.

[53] In modern use, the term party line has occasionally been used to market conference calling and voice bulletin board services.

Party lines were a focal plot point of the Doris Day and Rock Hudson film Pillow Talk.