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Fig. I X 2199Block schematic of systems with keysetKEM 32941 keyset KEM 32942 lamp relay set KFB 153013 lamp indicators4 transformerEquipment and OperationThe new staff locator system is composed of lamp indicators, keyset, lamprelay set and mains transformer, as in the block schematic of fig. 1.LampindicatorsThe system is based on the principle of visual signalling on lamp indicators.Two kinds of indicator may be used (figs. 2 and 3), the vertical type havingdifferently coloured lenses and the circular type red lenses. In the latter typethe lamps are 1.2 W and are fully visible at distances of 30 feet and above;in the former type the lamps are 3 W, being visible at 100 ft. and within asector of 180°. Both types of indicator are made for wall mounting and shouldbe placed about 6 ft. from the floor. Thirty-one visual signals are obtainable:five by the lighting of the five lamps individually, twenty-five by differentcombinations of two. three or four lamps, and finally one signal consisting ofall five lamps lighting at once. Since the two kinds of lamp indicator produceentirely different signal patterns, all indicators in one office should be of thesame type. Both types can incorporate a built-in buzzer.Fig. 2 X 4939Lamp indicator KNH 8311with differently coloured lamps in verticalarray. Dimensions: width 90 mm, height 232mm, depth 6l mmThe usual arrangement is to have one lamp indicator in each room andothers distributed as necessary in corridors, stock room, archives, mess roomsetc. The general rule should be that the signals should not disturb personssitting at their desks. These persons can be reached by the operator on thephone, and the whole object of the staff locator system is to contact peoplewho do not answer on their own extensions. The indicators should consequentlybe placed on the wall behind the occupant's desk so that they will cause himno disturbance but will be noticed by other people visiting him.The addition of a buzzer in the indicator may be advisable in corridorsand in localities where visual signals alone are insufficient. Irrespective of theFig. 3X 4943X4940Lamp indicators KNH 9501 for flushmounting(left) and KNH 9511 for surfacemounting(right)Dimensions:KNH 9501: diameter 85 mm, depth 53 mmKNH 9511: diameter 92 mm, depth 41 mm20