Throughout the state of California, the agency providing police services answers all 911 calls. The Alameda County Sheriff (ACSO), who serves Fairview and Five Canyons will answer your 911 call, whatever your need may be.
If you need police, the Sheriff will handle your call. If you need ambulance and/or the Fire Department, you are transferred to the Hayward Police Department (HPD) who is responsible for dispatching ambulances and Hayward Fire Department (who serves the FFPD area). While they are sending Fire and ambulance, they can provide medical instructions to you while you wait on the phone for help to arrive.
If you call 911 using a cell phone, most calls will go to the ACSO. However, it all depends on which cell tower picks up your call. Your call may be answered by ACSO, HPD, or CHP. If this happens, they will be sure to get you the help you need.
Consider programming your cell phone with the 10-digit phone number to the Alameda County Sheriff Department Dispatch Center. That number is 510-667-7721