The Telephone System of the British Post Office; A Practical Handbook (Paperback)

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. 1898 edition. Excerpt: ...six or eight a transfer board will be essential. The transfer board is the connecting link between the various sections. There are circuits from each section in the room to the transfer board, and means for connecting them together in any prescribed manner are provided. In order to render the working as rapid as possible the circuits between the sections and the transfer board are divided into two groups, known as A and B circuits. The A circuits are those upon which the section operator passes forward a call to the transfer board operator. The B circuits are those upon which the latter again passes forward the call to the required switch section. The A circuits then are used outwards from and the B circuits inwards to the sections. To each section there are allotted three A circuits and two B circuits--i.e., the section operator can pass forward three calls and receive two simultaneously if necessary. The A circuits are those upon which calls come inwards to the transfer board, and these are placed upon the slanting desk (Figure 93). The visuals in connection with these circuits are at the top of the slanting desk, and immediately below them come the combination keys, the object of which is to enable the transfer operator to speak and signal upon any circuit. The loop of each circuit terminates in a peg, and upon this circuit there is absolutely no apparatus. These pegs are to be seen above the desk. Each A circuit is provided with a peg, a visual indicator, and a combination key. It will be noticed that the board shown is only half fitted; but, it is, of course, a very simple matter to add more apparatus when required Combination Key. The insertion of a peg at the section drops the visuals at the section and transfer board. The operator...