Patent GB-880685-A (GB)
Title: Improvements relating to electric selective signalling systems
Inventor: HAILEY ALBERT MARTIN
IPC: G08B3/10
Filed: 1956-12-15
Abstract: 880,685. Electric selective signalling systems. ASSOCIATED ELECTRICAL INDUSTRIES Ltd. March 14, 1958 [Dec. 15, 1956], No. 31307/56. Drawings to Specification. Class 40 (1). In an electric location indicator system of the kind in which any member of a group of people may cause an indication of his whereabouts (at one of a number of specific locations) to be given by one or more indicator equipments set in response to signals transmitted from a signalling station, the indicator control equipment includes means for setting a plurality of separate indicator elements, included in a group of such elements, to positions requisite for building up a display of the member's identity. In the embodiment described, a member dials a 7-digit number, the first four digits of which represent the member's identity and the last three digits his location. The identity is preferably represented by two letters and a 2-digit number, a conventional telephone dial being used. The signal received at the control equipment is supplied to a relay-operated distributer which assigns the seven groups of pulses to respective uniselectors. The contacts of the three uniselectors assigned to the location number are connected so as to provide a binary coded representation of the location number on three groups of four leads, these acting as inputs for three indicators of the type described in Specification 721,683. The identity indication is obtained briefly as follows. The third and fourth groups of pulses cause respective contacts of the associated uniselectors to be marked, these contacts being connected to two uniselector seeking arrangements which come to rest at positions corresponding to the marked contacts and which are connected together so as to mark one of 50 output leads which are connected to the respective contacts of a further uniselector seeking arrangement which in turn takes up a position corresponding to its marked contact. This further seeking arrangement comprises a plurality of uniselector switches each having a plurality of banks of contacts, each switch having two banks which are used in seeking the marked contact, and 1, 2 or 3 of the switches being selected for simultaneous operation by the first two digits of the identity signal. This selection is performed by connecting selected contacts of the uniselector which is positioned by the first digit pulse group to respective wipers of a number of banks of contacts of the uniselector which is positioned by the second digit pulse group, the marked contact of this selected bank being used to select the switches of the further seeking arrangement. The output of the further seeking arrangement is in the form of ten groups of four leads each which are selectively marked to effect a display of the member's name on ten indicators of the type described in Specification 721,683. The control equipment may also include means for assigning a signal to one free indicator equipment in a group of such equipment, each indication persisting only for a limited time.