GB172321A - Improved calling apparatus for high frequency telegraphy - Google Patents

Abstract

172,321. Ges. f³r Drahtlose Telegraphie. Dec. 4, 1920, [Convention date]. Selective distant control systems.-A selecting- device operated by wireless signals, and suitable for calling subscribers to a news-distributing system, comprises a number of resonance relays arranged in series so that when one is actuated by a group of impulses of a given frequency it switches in the next, ready for closure by the succeeding series of impulses of a different frequency, and so on until finally the calling-alarm is actuated. The contacts of an initial relay 20 are actuated in synchronism with the signal impulses. The first impulse energizes a magnet 18 to close the circuit of a slow-release relay 17, and thereby through contacts 29, 30 to energize a series of holding-magnets 13 .. 16. The contacts 9 .. 12 are then ready to be closed by the pendulums 5 .. 8. The magnet 1 is already energized, and the first series of impulses will swing the pendulum 5 until it rests in the position shown, closing the contact 9. This contact completes the circuit of the next magnet' 2, so that the pendulum 6 will be swung into position by the ensuing series of impulses to energize the magnet 3 and so on, until finally the magnet 23 withdraws a latch to sound the calling-bell 21 and so notify the subscriber. At the end of the message the armature 29 falls away, and springs return the contacts 9 .. 12 to their normal positions ready for the next call.