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DeKalb County Technology Workshop July 12, 2005 - PowerPoint PPT Presentation

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DeKalb County Technology Workshop July 12, 2005. Agenda. Workshop Objectives Voice Communications Mobile Data Information Systems Key Considerations Discussion and Questions. Objectives. Develop a common understanding of common public safety communications and information technology terms

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DeKalb CountyTechnology WorkshopJuly 12, 2005

Agenda l.jpg

  • Workshop Objectives

  • Voice Communications

  • Mobile Data

  • Information Systems

  • Key Considerations

  • Discussion and Questions

Objectives l.jpg

  • Develop a common understanding of common public safety communications and information technology terms

  • Improve understanding of current technologies currently used by DeKalb County

  • Familiarize and demystify technology

  • Understand key trends

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Voice Communications

  • Single Channel Radio Basics

  • Coverage Extension

  • Multi-Channel Systems

  • Analog & Digital

  • Spectrum Choices

  • Standards and Regulatory Issues

  • Vendors

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Single Channel Radio Basics

  • Simplex

  • Half-duplex

  • Full-duplex

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Simplex Communications

  • Talk-around; car-to-car

  • Much like a kid’s walkie-talkie

  • Radios transmit and receive on the same frequency

  • No infrastructure required

  • Higher frequencies roughly limited to line of sight

Tx = 851.250

Rx = 851.250

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Simplex OperationMobile to Base (Talk-In)

Tx & Rx = 851.250

Mobile 2

Mobile 1

Tx & Rx = 851.250

Tx & Rx = 851.250

  • Dispatcher can hear Mobile 1

  • Mobile 2 is out of range

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Simplex OperationBase to Mobile (Talk-Out)

Tx & Rx = 851.250

Mobile 2

Mobile 1

Tx & Rx = 851.250

Tx & Rx = 851.250

  • Mobile 1 & 2 hear dispatcher

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Half Duplex

  • Use of 2 frequencies allows base station to “repeat” communications

  • Base station transmits on mobile’s receive frequency

  • Mobile/portable radios transmit on base station’s receive frequency

  • Half-duplex equipment does not allow simultaneous transmission and reception for users

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Half Duplex (Repeater) OperationMobile to Mobile

Tx = 866.250

Rx = 821.250

Rx = 866.250

Mobile 2

Mobile 1

Tx = 821.250

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Full Duplex

  • User can talk and listen simultaneously

  • Transmitter and receiver can be both powered and active full time

  • We are use to cellular phones working this way

  • Usually reserved for one-to-one communications

  • Not typical in wide-area private radio systems (one-to-many)

    • Wire line dispatch consoles can have “dispatcher priority”

    • User radios restricted to half-duplex operation

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Full Duplex (Repeater) OperationDispatch Priority

Tx = 866.250

Rx = 821.250

Tx = 821.250

Rx = 866.250

Mobile 2

Mobile 1

Tx = 866.250

Rx = 821.250


Wire line Console

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Frequency Utilization and Coverage Extension

  • Single-Site Repeated

  • Receiver Voting

  • Multicast

  • Simulcast

  • Regional Architecture

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Single-Site Repeated

Tx = 866.250

Rx = 821.250

Rx = 866.250

Mobile 2

Mobile 1

Tx = 821.250

Rx = 866.250

Mobile 3

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Receiver Voting

  • Improves talk-in coverage (from field)

  • Does not extend talk-out coverage (to field)

  • Compares and selects the best signal from multiple sites to be repeated from transmitter

  • Ensures that the best audio from receivers is processed

  • Economical solution for limited applications

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Rx = 821.250



Rx = 821.250



Receiver Voting (Portable)

Tx = 866.250

Rx = 821.250

Rx = 866.250

Mobile 2



Tx = 821.250

Portable 1

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  • Provides wide-area coverage by using multiple sites

  • Sites use different frequencies (frequency intense)

  • Variable density capabilities (some sites can have more channels than other sites)

  • Can have local area calls (calls that only appear on one site)

  • Cost effective use of infrastructure

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Tx = 866.250

Rx = 821.250

Channel 1

Tx = 868.500

Rx = 823.500

Channel 2

Rx = 866.250

Channel 1

Portable 2


Or Patch

Portable 4

Rx = 868.500

Channel 2

Rx = 868.500

Channel 2

Portable 3

Tx = 823.500

Channel 2

Portable 1

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  • Similar to multicast - wide area coverage by keying multiple transmitters simultaneously

  • Frequency efficient - each site uses the same frequencies

  • No variable density capabilities (all sites need the same number of channels)

  • All calls broadcast wide-area

  • Good for in-building urban coverage

  • Technically complex timing requirements – potential reception problems in overlap region

  • Expensive

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Tx = 868.500

Rx = 823.500

Channel 2

Tx = 868.500

Rx = 823.500

Channel 2

Rx = 868.500

Channel 2

Portable 2



Portable 4

Rx = 868.500

Channel 2

Rx = 868.500

Channel 2

Portable 3

Tx = 823.500

Channel 2

Portable 1

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Multi-Channel Systems

  • Conventional Systems

  • Trunked Systems

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Conventional Systems

  • Earliest form of radio communications systems

  • Most common type of two-way radio system

  • Individual agencies usually do not share channels

  • Frequencies are dedicated to specific channels and/or users

  • When channel is in use, others must wait their turn to use the channel

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Conventional Systems









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Simple to use

Lower cost


Supported by a large number of radio vendors

Usable in all frequency bands


Incompatible frequency ranges

Difficult to share channels

Inefficient use of resources

Separate systems for each agency

Difficult to coordinate on a wide scale

Conventional Systems

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Trunked Systems

  • Based on Telco queuing techniques

  • Developed to increase communications efficiency

  • Allows multiple users to share pool of channels

  • Computer controls radio and base stations

  • Radios have unique addresses

  • Talkgroups are “virtual channels” for groups of users that are temporarily assigned channels

  • Systems operate in 450, 700, 800 and 900 MHz bands

  • Ideal for regional systems serving many users from different agencies

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Trunked Communications

Radio 3003




“APD” Users

meet on

Channel “3”


Radio 3001 transmits

a channel request





Radio 3001










User depresses PTT

The System finds channel “3” available

The System Scans for all users on the “APD” talkgroup

Radio 3001 transmits to radio 3003 on the “APD”

talkgroup on channel 3

The System assigns channel “3” and transmits a message

for users on the “APD” talkgroup

With Users Identified, the System scans for an available channel

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Spectrum efficient

Better channel utilization

System redundancy

Fault tolerance

Talk group flexibility

Scalable for additional users and talkgroups on a wide-area basis

Enhanced features


Proprietary systems

Technically complex

High cost

Trunked Systems

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Regional Architecture



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Analog and Digital Networks

  • Analog

    • Continuously transmit radio waves from one point to another by converting audio signals into radio frequency signals

    • Can also carry data by converting it to an analog signal via a modem

  • Digital

    • Emerging trend in voice communications

    • Translate an audio signal into a digital bit stream of ones and zeros using “vocoder”

    • Stream is sent over the airwaves and decoded at the receiving end

    • Receiving radio translates the digital stream into an audio signal equivalent to the original voice message

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Analog Advantages

Proven, reliable technology

Simple technology

Lower component costs – cost to transition to digital can be very high

Vendor compatibility

Digital Advantages

Spectrum efficiency

Enhanced audio quality in fringe coverage areas

Improved encryption capabilities

Reduction of noise and interference

Analog and Digital Networks

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Spectrum Choices

  • VHF Low Band

  • VHF High Band

  • UHF

  • 800 MHz

  • 700 MHz

  • 4.9 GHz

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Emerging Standards

  • APCO Project 25 (Phase I)

    • Identifies common air interface (CAI) (vocoder interface, encryption)

    • Federal grants encouraging purchase of P25 radios

    • Only 1 infrastructure provider

  • APCO Project 25 (Phase II)

    • Will increase channel capacity by 2x over Phase I

    • Not fully defined; may support “competing standards”, e.g., TDMA & FDMA

    • Limited vendors with ability to offer an end-to-end solution


    • TErrestrial Trunked Radio – an open digital standard defined by the European Telecommunications Standards Institute

    • 4 channels per 25 KHz channel

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Regulatory Issues

  • Refarming

    • Focuses on reducing the bandwidths of Part 90 radio systems operating below 512 MHz

    • Reduction is in two stages:

      • 25/30 KHz to 12.5/15 KHz

      • 12.5/15 KHz to 6.25/7.5 KHz

    • Intended to increase efficiency of radio channels

    • Dates for implementation are a moving target

  • 700 MHz

    • Based on Balanced Budget Act of 1997 order to the FCC to allocate 24 MHz of spectrum for public safety usage

    • Channel availability dependent on television broadcast stations vacating operations on TV channels 60-69

    • Regional planning committees working on licensing plans

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Standards and Regulatory Issues

4.9 GHz

  • Broadband technology for public safety

  • Goal is to create Wi-Fi functionality in a frequency that is exclusive to public safety

  • Typically, same members working on regional plans are working on the 4.9 GHZ plan

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EF Johnson






DTC Communications

DX Radio Systems

EF Johnson





Midland Radio


Relm Wireless






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  • Mobile data is the transmission and receipt of information using radio frequency signals

  • Several types of users are supported by wireless technologies

    • Mobile/portable users

    • Remote users

    • Telecommuters

  • Benefits include:

    • Immediate access to critical information

    • Field personnel empowerment

    • Reductions in voice radio traffic

    • Remote interactive access to business applications

      • Work order processing

      • Maintenance Management and Inventory

      • Project Management

      • GIS

      • Office automation (email, etc.)

Mobile data l.jpg
Mobile Data

  • Agency-Owned Networks

  • Commercial National Data Networks

  • Telco Networks

    • iDEN

    • CDPD

    • GPRS

    • EDGE

    • CDMA 1xRTT

  • Other Mobile Data Technologies

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Agency-Owned Networks

  • Private radio networks owned by agencies

  • Limited data speeds available

  • Often able to re-use key components of voice infrastructures

  • Packet switched, message based technologies

  • Dedicated access for users

  • Can be conventional or trunked technology

  • Wide-area coverage system providers include Dataradio, EF Johnson, M/A-COM and Motorola

Agency owned networks41 l.jpg


Optimizes existing infrastructure

Agency control

Dedicated use

Potentially lower recurring costs

Can provide coverage where needed (everywhere)


Requires radio frequencies

Additional administration and maintenance responsibilities

Moderate data rates

Requires fixed infrastructure throughout entire coverage area

Capitalizing on technology advances can be costly

High initial costs

Agency-Owned Networks

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Commercial National Data Networks

  • Commercially developed data systems

  • Networks developed around population centers and major thoroughfares

  • Use proprietary, but widely available technology

  • Major networks include ARDIS and Mobitex

  • Some companies claim to cover 90% of the U.S. area containing 80% of the population – areas not well covered by other commercial carriers

  • Packet data network technology utilizing a satellite and terrestrial network

  • Data rates are noticeably slower (<8 kbps) than those offered by Telco's

Commercial national data networks43 l.jpg


Network store and forward allows packets to be stored for sending at a later time

Encryption available, if desired

Costs are proportional to usage – ideal for limited usage


Slow throughput

Not efficient for long messages

Commercial National Data Networks

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Telco Networks

  • No agency frequencies required

  • Minimal up-front costs

  • Lower hardware and software costs

  • Higher monthly recurring costs

  • Migration paths more feasible and economical

  • No site development required

  • Ability to provide for wide area roaming

  • Maintenance and service not the responsibility of the agency

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iDEN (Nextel)

  • Integrated Digital Enhanced Network

  • Motorola packet-switched technology

  • Throughput of 14.4 Kbps

  • No migration path decisions made to date

  • Nextel has submitted consensus plan to FCC for refarming 800 MHz spectrum

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Cellular Digital Packet Data (CDPD)

  • First commercial service widely adopted by public safety agencies

  • Utilized for traditional mobile data applications

    • Dispatch, status and vehicle-to-vehicle messaging

    • Automatic Vehicle Location (AVL)

    • Database inquiries

  • Maximum throughput of 19.2 Kbps – actual speeds typically 10-14 Kbps

  • Service is available in most metropolitan areas

  • Two major carriers offering national CDPD service plan to discontinue the service:

    • Verizon: Announced that CDPD service will end in 2005

    • AT&T Wireless (Cingular): Announced that CDPD service will end in June 2004. Recently retracted this statement; however, they still plan to shut down the network in the near future.

  • Not a viable alternative due to coming obsolescence

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  • General Packet Radio Services

  • Most widely deployed wireless technology worldwide

  • Maximum throughput of 115 Kbps – actual speeds typically 30-50 Kbps

  • Security concerns due to dynamic IP addressing

  • Major carriers include AT&T/Cingular and T-Mobile

  • Part of GSM migration path to faster data speeds that will minimize technology replacement costs for agencies.

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  • Enhanced Data Rates for Global Evolution

  • Backward compatible with GPRS; only modem replacement required

  • Maximum throughput of 384 Kbps – actual speeds typically 80-128 Kbps

  • Successor to GPRS

  • Rollouts to begin in 2004

  • Migration path leads to UMTS (Universal Mobile Telecommunications System) – throughput of 2 Mbps

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  • Code Division Multiple Access – Single Carrier Radio Transmission Technology

  • Digital spread spectrum technology – efficiently uses spectrum

  • Competing technology to GPRS and EDGE

  • Major carriers include Verizon and Sprint

  • Maximum throughput of 144 Kbps – actual speeds typically 40-60 Kbps

  • Migration path leads to CDMA 2000 – up to 2.4 Mbps in throughput

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Other Mobile Data Technologies

  • Wireless Local Area Networks

  • Mesh Networks

  • Satellite

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Wireless Local Area Networks

  • Quickly becoming integrated into wireless infrastructures throughout North America

  • Relatively inexpensive off-the-shelf technologies

  • Able to carry data at speeds up to 11 Mbps

  • Operate in unlicensed frequency bands above 2 GHz – security issues can be a concern

  • Used for short-range communications (100 to 500 feet)

  • Not intended for mobile vehicles seeking seamless coverage across a wide area

  • Commonly deployed by placing Wireless Access Points (WAP) at locations where mobile data users operate (major routes, stations, service shops, etc.)

Mesh networks l.jpg
Mesh Networks

  • RF Packet Technology (802.11x hybrids, ricochet)

  • Large Number of Low Power Repeaters

  • Wider scale than traditional wireless LANS

  • Transmission Across Very Wide Bandwidth

  • Wireless repeaters distribute traffic throughout network

  • Wired Access Points (WAP) connect network to internet

  • Up to 500 Kbps

  • Good for metropolitan areas

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Mesh Networks

.5 to

2 mi.



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Geosynchronous Earth Orbit

  • Orbit the earth at 22,300 miles

  • Rotates with the earth

  • Provide ubiquitous coverage

  • Propagation delays experienced

  • Service has focused on video (DirecTV, Dish Network), broadcasting and long-hall transportation

  • Mobile data rates are low speed 4.8 to 9.6 Kbps

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Low Earth Orbit Satellite

  • Orbit the Earth at 300 to 900 Miles

  • Require “Ring” of Orbiting Satellites to Provide Continuous Coverage

  • Provide Ubiquitous Coverage

  • Low data rates 2.4 – 9.6 Kbps

  • Iridium experienced significant financial problems, rescued by US Government

  • Initial promise has not emerged as originally hoped (Teledesic, etc.)

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Public safety information systems l.jpg
Public Safety Information Systems

  • Technology Overview

  • Industry Trends

  • Critical Success Factors

Public safety information systems59 l.jpg
Public Safety Information Systems

  • Computer Aided Dispatch (CAD)

  • Records Management System (RMS)

  • Mobile Data Computing (MDC)

  • Automated Field Reporting (AFR)

  • Jail Management System (JMS)

  • Geographic Information System (GIS)

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  • Used to handle all information related to receiving and dispatching emergency calls for service

  • Usually the primary point of entry for processing a call for service or an officer-initiated incident

  • Based on a geofile that uses map-based coordinates to verify caller and incident locations

  • Help prioritize calls for service and make unit recommendations for dispatching based on agency-defined criteria

  • Provide access to incident location history, warrants, hazards, etc.

  • Gateway through which to query multiple local, state and national systems

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Common Components

Call receipt and incident entry

Incident management


Unit and incident status monitoring

Address verification



Real-time mapping

Alarm billing




Management reporting


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  • A consolidated means of electronically collecting and storing reports and information

  • Provides agencies more analysis tools than any other system

  • Captures, maintains and analyses all agency and incident-related event information

  • Assists in daily operations of tracking and managing criminal and non-criminal events, investigations and personnel information

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Traffic Accidents


Pawn Tickets

Civil Processing




Fire Inspections

Inventory Tracking














related to

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Common Components

Master files (names, vehicles, locations, etc.)

Arrest and booking

Registration and permitting

Activity log

Incident and crime reporting (UCR, NIBRS, NFIRS)

Case management, investigations

Crime analysis





Property and evidence

Document imaging and workflow

Supplies and equipment inventory



Apparatus and vehicle maintenance

Animal control

Fire prevention


Mdc afr l.jpg

  • Designed to give field personnel mobile office technology

  • Three core components required to successfully implement:

    • Software

    • Hardware

    • Wireless Infrastructure

  • Via laptops and handheld units, allows for:

    • Proactive querying of databases

    • Initiation and receipt of CAD events

    • Viewing unit status

    • E-mail

    • Field reporting

    • Issuing citations

    • Accessing policies and procedures

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  • AFR automates incidents and reporting processes from the vehicle

  • Reduces time required for report writing, review and approval

  • Improves the accuracy, completeness and legibility of reports

  • Reduces report distribution time and effort

  • True automated field reporting (i.e., paperless processing of reports) is still in its infancy; however more and more agencies are beginning to implement it.

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Common Components

Dispatch operations

Database inquiries

Electronic messaging

Field reporting

Electronic mapping

Reporting and outputs

System security

Logs and audit trails

Magnetic stripe reading

Fingerprint scanning

Local, state and national queries

Automatic vehicle location


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  • Offers more complete automation of short-term jail management functions, including tracking of inmates and facility data

  • Operates very similarly to a traditional RMS, but tailored to the information management needs of a detention facility

  • Often available as a module of with RMS

  • Helps reduce paper-based logs and records

  • Normally integrated with automated fingerprint identification and mugshot systems

  • Barcoding technology used track property within the JMS

  • Provides several tools for data linkage, analysis and sharing with other justice information systems (i.e., prosecutor, courts)

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Common Components

Inmate tracking

Facility data

Cell management




Inmate programs

Medical history

Gang affiliations

Detention history

Visitor logs

Digital images (fingerprints, mugshots, etc.)


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  • Combination of GIS, mapping software and AVL provide effective tools to prevention and response efforts

  • Key public safety uses include:

    • Planning for emergency response

    • Determining crime prevention priorities

    • Analyzing current and historical events

    • Predicting and responding to future events

  • Allows for complex linkages and queries against a database, instead of storing information in flat files that maintain few relationships

  • Provides critical information to emergency responders en route to an incident to assist in tactical planning and response

  • Creation of an accurate and comprehensive geofile becomes critical for the ultimate success of almost every public safety system used by an agency

  • Maintenance is key

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Industry Trends

  • Increased demand for integrated public safety systems provided by a single vendor

  • Most leading systems are based on open-system designs

  • Minimal management reporting capabilities outside of canned reports – most vendors require users to develop reports using third party tools (Crystal, Access, etc.)

  • Increased use of mapping in dispatch centers and field units – proximity dispatching

  • Heightened demand for automated field reporting – more agencies are pushing report writing out to the officers on the street

  • Wireless infrastructures are the biggest technical constraint toward implementing automated field reporting

  • Starting to see more web-based applications . . . less client-server

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Critical Success Factors

  • Procure open, scalable systems

  • Identify all interface requirements before purchasing systems

  • Evaluate turnkey vs. best of breed procurement strategies on a case by case basis

  • Always begin by understanding and documenting current system capabilities

  • When in doubt, buy more training

  • Avoid underestimating the time and commitment of internal agency resources required to guarantee a successful implementation

  • Develop a data conversion strategy that is realistic; try to minimize the amount of data to be converted

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Key Considerations


Grade of




















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Michael P. Thayer

(310) 722-1745

Bret O’Connor

(310) 877-2227