Computer assisted dispatch and E-911 systems

Computer Assisted Dispatch & E-911

E911 which is short for enhanced 911 is a location technology that allows emergency services to locate the geographic position of a caller, regardless of whether the call is being made from a landline or a cell phone. When a 911 call is made it is routed to the nearest public safety answering point (PSAP) and then transmitted to the appropriate agency. The PSAP receives the caller's phone number and exact location from where the call is being made. Previous to 1996, if a caller was using a cellular phone they would have to contact their service provider to verify that they had a subscription service before their call was routed to a PSAP. In 1996, the FCC changed the way that cellular calls were routed, mandating that they go directly to a PSAP without any verification needed (E911, n.d.).

The roll out of E911 was done in two phases. The first phase was implemented in 1998. This phase required that cell phone carriers identify cell phones number and the location of the signal tower accurate to within a mile. In 2001 phase II was introduced. This phase required that all cell phone carriers in the United States provide handset or network-based location detection capabilities. These capabilities allow for the callers location to be determined by its geographic location accurate to within 100 meters (E911, n.d.). This geographic location is then displayed to the dispatcher along with giving them the capability to hold an open line for as long as is needed (McEwen, n.d.)

When E911 calls come in they are handled by an emergency response system. This system is better known as Computer Assisted Dispatch (CAD). This system can be used to send messages to a mobile data terminal or to retrieve and store data. CAD systems are usually run with one or two servers that are located in the dispatch office. These servers communicate with the mobile data terminals that are in the field in order to provide the first responder with the necessary information needed to handle the situation at hand (Encyclopedia>Computer Aided Dispatch, n.d).

CAD systems operate in a real time environment in police communication centers in order to: "(1) record information from citizens who call for police assistance, (2) assist dispatchers in sending patrol units and supporting units to scenes, (3) track the activities of all field units, and (4) provide data to police managers for improved resource allocation of patrol personnel" (McEwen, 2002).

The software that runs Computer Assisted Dispatch can be very simple or very complex. A simple system is known as a call for service program. This system combines a live, online program with off line features of a record management system. When CAD systems were first introduced they normally consisted of a mainframe system or mini computers linked to dumb terminals. The systems that are used today use a client server basis in which that data resides on the server and is linked to the workstation computers (Computer-Aided Dispatch Software Resources, n.d.).

CAD systems must contain certain elements in order to best facilitate the work of police dispatchers. These elements include:

Incident information- database of incident data

E911 interface-allows the CAD computer to be directly connected to the E911 software system

Location verification -- a database of standardized locations, used to match against incident locations

Information files-way of linking current incident details with any previous details

Incident display-way to list any current, pending or past incidents

Unit display-current list of available units

Incident dispatch-way of managing what units to assign to specific incidents

Time stamping-every action related to the phone call and incident is time stamped

Report generation-allows for generation of reports

External links-links to various criminal justice databases

Mapping- allows for real time maps to assist in finding locations and identifying the quickest routes to arrive at incident locations

Security- allows for different security levels to help control access to the data

These capabilities and features are all needed in order to make the receiving of the call and dispatching of services as quick and efficient as possible. They also allow for a police department to be connected to a local, county, state, and federal network of criminal justice databases (Computer-Aided Dispatch Software Resources, n.d.).

Typically emergency calls for service are automatically routed to dispatchers. When these calls are received the CAD system will recommend a unit assignment based upon a number of factors. These include: the location of the incident in question, they type of call that it is, and the availability of units for dispatch. Another feature that CAD systems have is to keep an online history of all calls that are taken. This history is usually kept for a six-month time period. This allows the dispatcher to have access to any prior calls regarding specific addresses, which may be helpful for the officer that is responding. It also maintains notes about locations that might contain important information for the officer. An additional helpful feature of the CAD system is that of time stamping. The system time stamps a call when it comes in, when it is assigned, and when it is completed. This helps for reporting purposes when trying to figure out how efficiently a police department is running (McEwen, 2002).

A further feature that a Computer Assisted Dispatch system can have is that of a mapping system. A mapping system can help a dispatcher better locate the source of a call along with helping to determine the best route that can be used to get to the scene. This feature allows for law enforcement dispatchers to obtain quicker response time during emergencies. This feature also includes the use of a GIS or Geographic Information System. This provides the dispatcher with geographical analysis and visual references to use in call dispatch (Computer Aided Dispatch (CAD) System Provides Mission Critical Mapping Capabilities for 911 Call Centers, 2008).