In July of 1877, a druggist in Hartford, Connecticut installed a switchboard to connect seven doctors to his store. This was the first switchboard, which was followed by a veritable explosion of these critical items in the telephone central offices. At the beginning, boys of 12-16 years were hired to operate the boards. Because of a lack of discipline, they were soon replaced by young women who set a far higher standard. As more telephones were added to each central office, switchboard demands increased astronomically. A rule of thumb: The number of switching appearances must equal the product of half the number of phones times the total number of phones (for 50 phones, one needs 1250 appearances).
A small switchboard can be handled by one operator, who plugs connecting cords into the socket (jack) of the calling party, and a matching connecting cord into the socket of the called party.As the number of telephones in the central office increases, the switchboard must grow larger. Finally, it is so busy that one operator cannot handle all of the calls on the lines. The fix? Another switchboard, identical to the first, set right beside the first one, connected to the same circuits as the first, and worked by a second operator. Either operator can answer a caller; together, they can answer twice as many calls.
The size of a single switchboard is limited by the reach of the operator, who has to plug the connecting cords into any two sockets on the board. The number of "multiple appearances" (all the same sockets that were in the first switchboard) is set by the telephone caller activity. Historical precedent set the telephone central office size to 7,500-10,000 telephones. If more phones than that were required, a new central office was built.
Long-distance switchboards followed the same above practices. However, instead of having jacks for the subscriber telephone, they had jacks for each destination city. In 1984, the long-distance branch of the Bell System had 20,000 operators. It now has 8,000 operators, a number that is steadily being whittled down. The last manual long-distance switchboard using cords, located in Peabody Massachusetts, was shut down in September, 1996.
Source : www.moah.org/exhibits/archives/talkingwires.html
A small switchboard can be handled by one operator, who plugs connecting cords into the socket (jack) of the calling party, and a matching connecting cord into the socket of the called party.As the number of telephones in the central office increases, the switchboard must grow larger. Finally, it is so busy that one operator cannot handle all of the calls on the lines. The fix? Another switchboard, identical to the first, set right beside the first one, connected to the same circuits as the first, and worked by a second operator. Either operator can answer a caller; together, they can answer twice as many calls.
The size of a single switchboard is limited by the reach of the operator, who has to plug the connecting cords into any two sockets on the board. The number of "multiple appearances" (all the same sockets that were in the first switchboard) is set by the telephone caller activity. Historical precedent set the telephone central office size to 7,500-10,000 telephones. If more phones than that were required, a new central office was built.
Long-distance switchboards followed the same above practices. However, instead of having jacks for the subscriber telephone, they had jacks for each destination city. In 1984, the long-distance branch of the Bell System had 20,000 operators. It now has 8,000 operators, a number that is steadily being whittled down. The last manual long-distance switchboard using cords, located in Peabody Massachusetts, was shut down in September, 1996.
Source : www.moah.org/exhibits/archives/talkingwires.html
No comments:
Post a Comment