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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.
In 1971, Southern Bell had announced plans for phase-out of party lines in North Carolina.
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.
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.
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 often led to traffic congestion in the telephone network, as the line to a destination telephone was often busy.
Illinois State University terminated its last party line in 1990.
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, and to make a call outside the exchange area it was necessary to call the exchange to place a call.