Chicago's New 911 System
Chicago has implemented a new, state-of-the-art police Emergency Communications Center Network. Costing more than $215 million dollars, the system enables dispatchers to quickly transmit detailed historical and event data to police officers responding to emergencies and crimes in progress. This provides police officers with much more information about a situation before they must confront it. The new network also links firefighters andemergency medical service technicians to help them respond to emergencies.
The system promises that 99 per cent of all calls to Chicago's 911 emergency number will be answered within oneor two rings - most in 1.2 seconds. Under the previous manual system, only 60 per cent of the 911 calls were answered within two rings. Calls took an average of three times as long to be processed.
From a technological standpoint, the secure communications network will use 155 Mbps and 655 Mbps Synchronous Optical Network (Sonet) backbones. This is the standard for high-speed data transmission over fiber optic cable. The link between the emergency dispatchers and the administrative personnel are 185 Ascom- Timeplex routers from Digital Equipment Corporation. Unix-based workstations and a Microsoft Windows NTversion 3.51 connects 215 firehouses, police stations and public safety facilities. The Microsoft server was chosen for its ability to handle large Oracle databases.
The hub for the network's 176 miles of fiber optic cable is the Madison Avenue 911 emergency headquarters. The Ascom-Timeplex routers provide speed and redundancy. They are also able to integrate a wide variety of disparate network protocols. The devices also use Express Routing Software. This enables the emergency network to prioritize the various data traversing the network to deliver maximum bandwidth with the least amount of overhead.
The 108 Dispatchers used Digital Unix computer-aided dispatch workstations to access electronic databases containing detailed maps of city streets and buildings.
The procedure is as follows:
i) Telephone calls to the 911 Emergency Communications Center are routed through the 176-mile, cityowned fiber optic Integrated Services Digital Network. Callers are connected in less than 1.2 seconds to one of 108 emergency 911 dispatchers.
ii) Telephone calls are logged and answered. The caller's name and address are displayed on a Digital Unix-based workstation. The 911 operator verifies the information and transfers the call to the police or fire dispatcher.
iii) The 911 dispatcher accesses the Oracle database to call up detailed graphic maps of any street and building in Chicago. The maps give dispatchers instant access to exact street locations, the best routes to get there, and detailed building descriptions. These include entrances, closest cross streets, nearest fire hydrant, owner's name and whether hazardous materials are stored on the property.
iv. Domestic disturbance records indicate previous criminal records. Separate computer screens display telephone numbers and addreses of municipal and governmental agencies. Touching the screen will dial the selected agency.
v. Information is transmitted through the routers and backbone to computer terminals in squad cars andfire engines and hand-held devices carried by officers, firefighters and other personnel.Read the caselet carefully and answer the following questions:
1. What potential security problems exist with the network? What will be the major types of controls that will be needed to ensure quality and security of such an information system? What are the various types of transmission cables used in telecommunication networks?
2. Here, Chicago's police Emergency Communications Center Network uses fiber optic cable for data transmission. What are the advantages of fiber optic cable over other types of cables?