They both have a very important job. by working together, one tells where and what and the responding officers would find the place and do there job by helping and fixing!
When you dial 911: The signal goes to the phone company's database. There, it finds out the information that you supply the phone company when you start your service. Then your signal, along with the information is sent to us in the form of Automatic Name and Location information (ANI/ALI).
