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 in order to determine according to the ringing cadence if they were the party being called on any given ring.Secondly, if any party on a given line should so be inclined, there was the insidious opportunity to listen in on other parties' calls.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, becoming a cultural fixture of rural areas for many decades.The rapid growth of telephone service demand, especially after World War II, resulted in a large fraction of party line installations in the middle of the 20th century in the United States.This distinctive ring would alert all parties on the line who the call was for.Three short rings signified the call was for the party with the S letter and so on.
Such laws also provide penalties for abuse by falsifying emergency situations.
To signal specific subscribers on party lines selectively, telephone operating companies implemented various signaling systems.
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).
This often led to traffic congestion in the telephone network, as the line to a destination telephone was often busy.
In December 1942, University of Tennessee's strategy in an American football game versus University of Mississippi was revealed to the opposing coach as a telephone on the Ole Miss team's bench had been inadvertently wired to the same party line.