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manual abstract
The Model 878HL has a slide switch for low or high impedance selection. The wide band frequency response is smooth and peak free, with a slight rise above 2K Hz to give that "natural" highly intelligible sound. The microphone and relay switching is accomplished with long life DPDT professional leaf switches and choice of either a simple push-to-talk bar with locking capabilities, or lift-to-talk operation, to give years of dependable, trouble free performance. The lift-to-talk operation can be disabled with a slide switch located under the microphone base. The 878HL is manufactured to take normal abuse and retain its performance over a long life. Four molded "feet", non-skid, non-marring, permanently resilient, are located under the zinc die cast base. Supplied with 2.1m (7 ft.) of four conductor, two shielded cable, the Model 878HL microphone circuit is wired normally open. Available in black. 878HL HI-LO DYNAMIC DESK PAGING MICROPHONE APPLICATIONS PUBLIC ADDRESS AND PAGING: A superior microphone for installations where quality of reproduction is desired. Modern styling plus rugged construction and environmental resistance will provide dependability in such applications as airport control towers, police, fire and taxi dipatching, office communications, paging in department stores, restaurants, bowling alleys, factories, schools, fast food outlets, movie theaters, etc. back to main page SPECIFICATIONS FOR 878HL Specifications C€ Element: Dynamic Pattern: Omnidirectional Frequency Response: 50 to 12,000 Hz Output Level: HiZ: -55dB (0dB = 1 volt / microbar) -151 dB EIA LoZ: -58 dB (0dB = 1mw / 10 microbars) -76 dB (0dB = 1 volt / microbar) -152 dB EIA Impedance: HiZ: 40,000 ohms, matches 100K ohms or greater LoZ: 400 ohms, matches 125 to 1000 ohms Switch: Control: DPDT professional long life leaf switches operated with a simple push-to-talk operation. Impedance: DPDT slide switch located on underside of the microphone Cable: 2.1m (7 ft.) of heavy duty four conductor (two shielded) cable Dimensions: 238mm (9-3/8") high; 110mm (4-11/32") wide 148mm (5-27/ 32")deep Weight: 687 grams (24-1/4 oz.) Finish: Durable molded Cycolac in black with die cast base painted in a complimentary color IMPEDANCE The Astatic Model 877HL is a duel impedance microphone. The high impedance position is 40,000 ohms and the low impedance is 400 ohms. The low impedance position is recommended for long cable length requirements. Cable lenghts of 30.5m (100 ft.) or more can be used in this position without loss of level or deterioration of high frequency response. CABLE END CONNECTIONS HI IMPEDANCE: Connect the red lead to the audio input, the black lead and shield to ground, and the white and green to relay control LOW IMPEDANCE: Connect cable leads red and black to balanced line input, shield to ground, white and green to relay control. PHASING Positive pressure (movement of diaphragm inward) will generate a positive voltage on the red cable...