Telephone Service Volume 112

Telephone Service Volume 112

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1921 edition. Excerpt: ...the order in which they will be handled. Two calls may be handled simultaneously only when the calling lines have terminals on the same bank and are in different subgroups and when there is an idle finder in each subgroup. Equipment is also provided for distributing calls among all the finders in each subgroup. When a line finder is started the sender selector is also started and seeks an idle sender unless it is associated with one at the time. The line connection from the finder to the first selector is opened during the time required for finding the calling line and an idle sender. When the terminal of the calling line is reached by the brushes, the finder is stopped, the line relay is cut off, thereby disassociating the line and the finder start-control equipment, and the third wire of the calling line is made to test busy as described for a line-switch. When both the calling line and an idle sender have been found the calling line is connected through to the sender and the sequence switch of the first selector is advanced to the first operating position. On an originating call the line finder remains in the operated position until the first selector releases it by establishing a disconnecting circuit. When a terminating call is received the cutoff relay is operated by the selector making the line connection. In this case the operation of the cut-off relay merely cuts off the line relay. Message registers may be associated with individual and two-party lines and operated as described for line-switches. Order of Line Selection.--There are four kinds of selectors associated with panel-type line banks. These are known as district, office, incoming, and final selectors and they are here given in the order in which they are chosen more

Product details

  • Paperback | 88 pages
  • 189 x 246 x 5mm | 172g
  • United States
  • English
  • black & white illustrations
  • 1236931823
  • 9781236931825