. The telephone system of the British post office. A practical handbook . These are fitted infour strips. The top strip consists of five visuals, underneath which isplaced the strip of five switch-springs corresponding to them ; then comesthe second five visuals and switch-springs. Two transfer circuits are provided from Section i to Section 3 and twofrom I to 4. Section 2 can reach all save Section 4, between which twocircuits are provided. In the case of five sections two circuits between the 104 Transfer Circuits. following sections must be provided: i and 3, 1 and 4, i and 5, 2 and 4,2 and
. The telephone system of the British post office. A practical handbook . These are fitted infour strips. The top strip consists of five visuals, underneath which isplaced the strip of five switch-springs corresponding to them ; then comesthe second five visuals and switch-springs. Two transfer circuits are provided from Section i to Section 3 and twofrom I to 4. Section 2 can reach all save Section 4, between which twocircuits are provided. In the case of five sections two circuits between the 104 Transfer Circuits. following sections must be provided: i and 3, 1 and 4, i and 5, 2 and 4,2 and 5, 3 and 5. For six sections: i and 3, i and 4, i and 5, i and 6,2 and 4, 2 and 5, 2 and 6, 3 and 5, 3 and 6, 4 and 6. Where the number of sections exceeds this a special transfer switch isusually employed ; but this will be described in Chapter XVIII. The connections of the visuals and switch-springs to the tags is in-dicated in Figure 90. It will be seen that they are precisely as shown inthe case of the B switch section, and that when joining up a transfer <^=^. 8^o%pt Srriia^ Sprtpf^S y/atai fpJicator-SS draipf Sr„fc^S/>rxpg»S S-fotpf - Figure 91. circuit between sections i and 3, tag 21 goes to tag 21, and tag 23 to 23 ofthe other section. Similarly the ends of tags 47 and 48 are reason of this is obvious. Tags 47 and 48 are respectively connectedto the positive and negative poles of the battery. Tag 47 is connected tothe top springs of all the switch-springs teed together, and tag 48 is con-nected to the teed bottom springs. The visual signalling wires are con-nected to the respective circuits to which they are intended to work. Thecorresponding loops are 83 and 84 to loi and 102. Junctions to Post OJtce Local Switch. 105 Where there are more than three sections the tags 47 and 48 should betaken to the test board and there joined to the battery by means of Ulinks. If this is not done very great difficulty will be experienced intracing faults, owin|
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Keywords: ., bookcentury1900, bookdecade1900, booksubjecttelepho, bookyear1901
