. American telephone practice . ect either the high or the lowfrequency machine between either side of the line and ground. Twoof the bells of the four sub-stations are bridged between one limbof the line and ground, the other two being similarly connectedwith respect to the other limb. Each bell has associated with it aretardation coil and a condenser, the arrangement being such that 458 AMERICAN TELEPHONE PRACTICE. one of the bells on each side of the line will respond only to cur-rent from the high frequency generator, and the other only to thatfrom the low frequency generator. As will be s
. American telephone practice . ect either the high or the lowfrequency machine between either side of the line and ground. Twoof the bells of the four sub-stations are bridged between one limbof the line and ground, the other two being similarly connectedwith respect to the other limb. Each bell has associated with it aretardation coil and a condenser, the arrangement being such that 458 AMERICAN TELEPHONE PRACTICE. one of the bells on each side of the line will respond only to cur-rent from the high frequency generator, and the other only to thatfrom the low frequency generator. As will be seen from the circuit stations, I and 3 are high-fre-quency stations, and at each of these the bell is shunted by a low-wound impedance coil, this parallel circuit being placed in serieswith a one-microfarad condenser. The bells at stations 2 and 4are adapted to respond to low frequency currents only, and there-fore are placed in series with a two-microfarad condenser and a HlQHFREQUENCY hi«;h FREQUENCY l-OW FREQUENCY FREQUENCY. FIG. 337.—LEICH PARTY-LINE SYSTEM. high-wound impedance coil. Each limb of the line carries onehigh and one low frequency station. If the low frequency generator is connected with the limb, a, ofthe line, by throwing ringing key, 2, some current will pass toearth through the bell of both stations 1 and 2. Most of the cur-rent that passes to ground at station 1 will, however, pass throughthe shunt coil around the bell, and, moreover, the low-capacity con-denser proves a somewhat serious barrier to the slowly fluctuatingcurrent. On the other hand, all of the current that passes to groundat station 2 passes through the bell magnets, This current is of PARTY LINE SYSTEMS. 459 sufficient magnitude to operate the bell, the larger capacity con-denser allowing the low frequency current to pass through it moreeasily than that at the other station. The bell at station 2 rings,therefore, while that at station 1 does not. If ringing key, 1, is thrown, the high fr
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