14 Keysight 81618A/9A and Keysight 81620B/3B/4B/6B/8B Optical Heads User’s Guide1 Getting Started with Optical HeadsSafety ConsiderationsThe following general safety precautions must be observed during allphases of operation, service, and repair of this instrument. Failure tocomply with these precautions or with specific warnings elsewhere in thismanual violates safety standards of design, manufacture, and intendeduse of the instrument. Keysight Technologies assumes no liability for thecustomer’s failure to comply with these requirements.Before operation, review the instrument and manual, including the redsafety page, for safety markings and instructions. You must follow these toensure safe operation and to maintain the instrument in safe condition.Safety SymbolsThe apparatus will be marked with this symbol when it is necessary for theuser to refer to the instruction manual in order to protect the apparatusagainst damage.Caution - hot surfaceMagnetic fields - may interfere with a pacemaker.WARNING The WARNING sign denotes a hazard. It calls attention to a procedure,practice or the like, which, if not correctly performed or adhered to, couldresult in injury or loss of life. Do not proceed beyond a WARNING signuntil the indicated conditions are fully understood and met.CAUTION A CAUTION notice denotes a hazard. It calls attention to an operatingprocedure, practice, or the like that, if not correctly performed oradhered to, could result in damage to the product or loss of importantdata. Do not proceed beyond a CAUTION notice until the indicatedconditions are fully understood and met.