The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 302
d onthe proper leg of the lineto ring the bell of the sub-scriber required, throughthe relay contact andearth connection. Fig. 280 also shows thecombination of ringing keysused by the operator forringing on a line connectedon the right-hand side. This arrangement,though a great improve-ment for… … Fig. 281 276 PRACTICAL TELEPHONE HANDBOOK upon the principle that the impedance of a retardation coilvaries directly as the square of the frequency of the currentwaves traversing it, while the impedance of a condenser variesinversely as the square of the frequency. Fig. 281 gives the connections of…
Telephone
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