the cellphone through three or more cell towers position determining equipment or pdb uses the inputs from the towers to triangulate to determine the originating position of the call some cellphones carry a global positioning system gps unit inside the phone such phones use three or more satellites to triangulate the call 39 s originating position often a combination of tower and gps sources will be used to satisfy the e911 mandates the pde resolves its inputs into a location expressed as a latitude and longitude or lat long for the call 39 s originating point in a matter of milliseconds the call is routed through several different components within the network an hlr or home location register determines the caller 39 s home telephone number a vlr or variable location register processes roaming callers by assigning a temporary telephone number to the calling phone an scp or service control point manages call routing and billing an mpc or mobile positioning center determines the originating position of the call the scp communicates with the mpc to retrieve the position information and forward it to the e911 dispatcher the invention is a module integrated with the mpc information and is called a location management platform or lmp during the interval of milliseconds allotted to call processing during call setup the invention determines what public safety answering point or psap should be notified on the caller 39 s behalf the invention 39 s ability to determine the correct psap within a few milliseconds makes the invention commercially and statutorily acceptable in support of the e911 application a second application is location based billing or lbb for mobile telephone service using the same pde inputs as.