During an emergency, you may be the first or only person available to report it to the appropriate public safety agency (police, fire, or rescue).  When this happens, the most crucial information you must provide is the nature of the emergency and its precise location.
    The primary purpose of autopatching is the capability to place telephone calls to public service agencies if you need to report an emergency.  That may not always be as simple as it sounds.  There are also technical considerations that have the potential to create confusion.
    More than 30 million Americans are served by Enhanced 911 service.  This service permits Public Service Answering Points (PSAPs) to automatically identify the number of the telephone from which a 911 call is placed and to pinpoint its location.  Many repeaters are set up so hams can dial 911 via their radios.  Enhanced 911 Service complicates matters.  If you dial 911 via repeater autopatch, the PSAP attendant receives a computer display of the location of the repeater's telephone equipment.  Unless the emergency happens to be at the repeater site, this information is useless and misleading.  Instead, you must inform the PSAP attendant that the emergency is located elsewhere.
    You must understand that the PSAP attendant has no interest in hearing that you're a ham radio operator, that you're using a repeater autopatch or what you call sign may be.  The main concern is the emergency and exactly where the repsonse personnel must be sent.  This is no time to describe Amateur Radio, repeaters or autopatching.  The PSAP attendant probably doesn't care about your name, much less your call sign or other mumbo-jumbo.  If they need to know more, they will ask you.  They may ask if there is a fire, if other vehicles are involved, if traffic is obstructed, whether there is a chemical spill or how recently the accident happened.  Be brief but thorough.  Also, be sure you and the PSAP attendant understand that once your call is completed, they will not be able to call you back.  For this reason, make sure they are 100% clear of the situation, then you may terminate the call.