GB828227A - Alarm signal generator - Google Patents

Abstract

828,227. Alarm signal generators. INTERNATIONAL MARINE RADIO CO. Ltd. (Standard Radiofabrik A.B.). Oct. 30, 1956, No. 33066/56. Class 118 (2). [Also in Groups XXXIX and XL (c)] An alarm generator comprises a container housing means for generating alternately two electrical signals of different frequency, a loudspeaker for reproducing the signals, a support for a telephone hand-set and a switch, whereby when the hand-set is placed on the support the switch operates causing the alarm signal to be emitted from the speaker and received by the microphone. The generator may be used for producing alternate tones of 1300 and 2200 cycles per second for marine radio distress signals. In Fig. 2 the container has one portion covered by a lid Q for holding the batteries and another portion R for holding the generator circuit. The container is supported in a U- shape mounting having at its top two rails E along which slides a strip B to hold the box in position. The rails are connected by a spring C and a further strip D so that a telephone handset J may be supported on them in proximity to a loud-speaker G connected to the output of the generator circuit. Contact between the hand-set and a switch A sets the circuit into operation and operates the key K on the telephone receiver so that the two tones emitted from the loud-speaking device will be picked up by the telephone receiver L and radiated by the associated radio transmitter. The tones are generated by a circuit (not shown) comprising two transistor oscillator circuits arranged to operate alternately by connecting them in a multivibrator circuit.