GB1345080A - Apparatus for a signalling-and indicating installation - Google Patents

Abstract

1345080 Selective signalling S G ANDERSSON 7 Jan 1972 [11 Jan 1971] 809/72 Heading G4H An apparatus for use at a station of a signalling and indicating installation, comprises a transmitter having a key controlling coding means to simultaneously generate a control signal and at least two address signals, and a receiver having decoding means controlling a lamp via storage. In a hotel, such apparatus is provided with respect to each hotel room, at a desk clerk (or room attendant) location, at a cashier location and at a maid supervision location. When a key is closed at a transmitter, a pulse is applied via a differentiating element, an amplifier, and diodes, to a predetermined two (respective to the associated hotel room) of a set of address wires, and to a predetermined one of two control wires. The address and control wires, and two power supply wires are common to all the apparatuses. At a receiver, the state of a lamp is controlled by a flip-flop which is set when pulses arrive on the respective two address wires and on a predetermined one of the control wires, and is reset when pulses arrive on the two address wires and the other of the control wires. Using this system, the desk clerk can light the lamp corresponding to a given hotel room at all three locations, and the cashier can extinguish it. Bistable relays may replace the flip-flops. Two extra power supply lines for the lamps, one carrying clock pulses to give intermittent energisation, may be provided, together with an extra control wire. In this modification, both positions of some keys can produce output to the wires via respective differentiators, &c., and lamps associated with other keys use two bistable relays, controlling continuous and flashing energisation respectively. In this case, the cashier's action changes the maids' supervisors' lamp from continuously on to flashing and she can extinguish it when the room is ready to be reoccupied.