The United States telephone industry introduced direct distance dialing ( DDD ) to the public in Englewood.
2.
Even shorter numbers used to exist in previous decades, especially in small towns and before direct distance dialing became universal.
3.
Routing tables are constructed with no duplicate numbers, so that direct distance dialing service can be provided to all digit telephone numbers.
4.
In preparation for direct distance dialing, AT & T and the Bell System developed the North American Numbering Plan in the 1940s.
5.
The system was implemented in the USA beginning in 1946 and was gradually superseded by Direct Distance Dialing ( DDD ) by 1965.
6.
An unusual feature of the telephone network was that, in most cases, direct distance dialing for long-distance calls was not possible.
7.
The introduction of direct distance dialing ( DDD ) in the 1950s required the addition of automatic number identification equipment for centralized automatic message accounting.
8.
The adoption of seven-digit local numbers ( 2L-5N ) was chosen as the requirement for direct distance dialing and progressively deployed starting the late 1940s.
9.
The Yukon was also covered by 403, not 604, since its lines were handled, prior to Direct Distance Dialing, by operators in Edmonton, Alberta.
10.
This dramatization ( and others like it ) illustrates the cumbersome, costly and time-consuming process needed for long-distance calling before direct distance dialing was available.
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