TODAY’S PATENT – MULTIPLE SWITCH-BOARD FOR TELEPHONE-EXCHANGES
Today’s patent was invented by Leroy B Firman and was granted patent on January 17, 1882, bearing patent no. US252576A.
Prior in his invention the individual lines were grouped upon a single switch-board at the central office, or grouped upon two or more boards. In the latter case trunk lines were used when it was necessary to connect a line of one board with a line of another board. A large exchange was thus divided up into a number of exchanges, which could be worked together, when occasion required, as one, by means of trunk lines between the boards. He soon found, however, that a single switch-board would not accommodate the number of attendants necessary to do the switching for an exchange of four or five hundred subscribers.
This invention consists in providing two or more switch-boards instead of one. as heretofore, and so connecting the several lines there- 5 with that any two lines can be connected on either of the boards, and also apparatus whereby attendants at a given board may without delay see what lines are connected at other boards than their own.