Three short rings signified the call was for the party with the S letter and so on.To signal specific subscribers on party lines selectively, telephone operating companies implemented various signaling systems.
Party lines in the United States were ineligible for Universal Service Fund subsidies and telephone companies converted them to private lines to benefit from the subsidies.
Universities also phased out the systems, which were once common in student dormitories.
The exchange rang a distinct ring down the Gundabluie 1 line, signalling the party's corresponding letter in Morse code.
This distinctive ring would alert all parties on the line who the call was for.
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.
By the 1980s, party lines were displaced in most localities as they could not support subscriber-owned equipment such as answering machines and computer modems.
The electro-mechanical switching equipment required for their operation was rapidly becoming obsolete, supplanted by electronic and digital switching equipment.
Farmers in rural Australia used party lines, where a single line spanned miles from the nearest town to one property and on to the next.