OBS

(1) Omni Bearing Selector. A panel instrument which contains the controls and circuits to select an omnibearing and determine the TO-FROM indication. / Omnibearing Selector-part of a VOR receiver system, which allows the pilot to select a course to or from a VOR station (2) Observer (3) Ocean Bottom Seismometer (4) On-Board Service (5) On-Board Switching (6) Out of Balance Switch (7) Optical Bypass Switch.