. The telephone system of the British post office. A practical handbook . es are again deflected to theright, thus serving as an instruction to the operator to remove the plugs,which is accordingly done. It should be noted that the relay tongue isbiassed by means of the spring and held on to the right contact; thus thestoppage of the permanent current (which holds it off the left handcontact point) allows the spring to close the local circuit, thus effecting aring. The operators connections are shown in Figure 58. The outer springsfrom the plug-switch pass through the central springs of the sp
. The telephone system of the British post office. A practical handbook . es are again deflected to theright, thus serving as an instruction to the operator to remove the plugs,which is accordingly done. It should be noted that the relay tongue isbiassed by means of the spring and held on to the right contact; thus thestoppage of the permanent current (which holds it off the left handcontact point) allows the spring to close the local circuit, thus effecting aring. The operators connections are shown in Figure 58. The outer springsfrom the plug-switch pass through the central springs of the springs operating Connections. 60 labelled direct. through the inner springs, through the reversedsprings, through the generator springs to the secondary coil and receiverof the operators telephone. The receiver is joined to an ordinary peg andis inserted as shown, and the transmitter is similarly connected. Theright-hand inner spring is connected through the secondary of theinduction coil S to the left spring, through the tip along the shoulder back AEvCReeO qff^ERATOII. Figure 58. to the inner left spring. The path of the primary circuit is from theright hand battery to the right hand long transmitter spring, through thetransmitter back to the other pole. When the transmitter and receiverare reversed the other batteiy is inserted. The pegs must be inserteddiagonally. The depression of the first peg puts a battery to line in onedirection, and the second key puts on the battery in the reverse generator is put on to the circuit by depression of the third key. 70 The Telephone System of the British Post Office. CHAPTER of Permanent Current System. In dealing with trunk, , inter-town wires, we confront quite a newaspect of the question. The National Telephone Company have estab-lished exchanges in nearly every town of any size, and subscribers linesterminate at these centres. The trunk lines connect together the differentcentres or districts, and termi
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Keywords: ., bookcentury1900, bookdecade1900, booksubjecttelepho, bookyear1901
