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Glossary
A - D
- A -
ACU 1000 -
  • See Gateway Switch.
Analog -
  • Analog - As a technology, analog refers to a continuously varying waveform.  The way in which it varies, carries information.  (Digital on the other hand makes a conversion from the analog waveform into digital bit stream where bits are assigned a value of either “1”s or “0”s.  This is termed a binary bit stream.) Analog technology has been around for decades.  See Digital below.
- B -
Backbone Site -
  • Sites that make up the project's digital microwave backbone network. This network provides the essential link for voice and data signals sent from the mobile radio base stations in the tower on the backbone site to central network control centers. Backbone sites across the state make up "loops" over which voice and data signals travel on microwave. Backbone sites are also known as core sites.
Band (Radio) -
  • A band is a small section of the spectrum of radio communication frequencies, in which channels are usually used or set aside for the same purpose.  Each band has a basic band plan which dictates how it is to be used and shared, to avoid interference and to set protocol for the compatibility of transmitters and receivers. There are five primary public safety bands:
    • VHF Low which operates in the 30-50 MHz range, commonly referred to as “Low Band”
    • VHF High which operates in the 138-174 MHz range
    • UHF which encompasses 406-512 MHz
    • 700 MHz that goes from 764 to 806 MHz
    • 800 MHz operations that goes from 806 to 866 MHz
Broadband -
  • In telecommunications, this is a term that refers to a signaling method. It includes or handles a relatively wide range of frequencies, which may be divided into channels.  The wider the bandwidth, the more information can be carried.
- C -
Conventional Radio System -
  • A conventional radio system basically is one that is not trunked.  Conventional systems can be simplex (base to mobile) or repeated (where the signal from a low power/low elevation mobile or portable radio is automatically rebroadcast usually with higher power and/or higher elevation.   A repeater system extends the line of sight operating range of communications beyond that achievable directly between users on the ground.  Conventional radio repeater systems can be either analog or digital.
     
    A conventional radio repeater system typically consists of one or more channels, each made up of a pair of frequencies (input and output) and a user selects the frequencies being used by changing channels on his or her radio.
     
    Conventional radio repeater systems are inefficient when used by a large number of users because they only offer a single talk path through the repeater.  Users must standby until the system is idle to initiate a conversation.
Co-Location Site -
  • A site with an existing communications facility that the State Radio Project can join in partnership. This could mean sharing space in a building or on a tower, perhaps with a county, a utility or wireless phone company. (Scope Level 1).
Construction Phase -
  • The building of the tower, shelter and site infrastructure.
Core Site -
  • See Backbone Site.
Coverage -
  • Coverage is the amount or percentage of area reached by a communications medium.  Coverage depends upon the definition of how much signal the user must have for a communication.  If the requirement is for small levels of signal, the coverage area can be large.  If the requirement is for high levels of signals, the coverage area shrinks. 
     
    The amount of signal required depends upon whether they support vehicles in motion (the greater the speed, the more signal that is required) and upon the amount of losses that are expected (for example, it takes more signal to penetrate high foliage trees than it does to penetrate winter trees that may have no leaves). 
     
    In order to equate coverage between systems, it is imperative to know what level of signal is required.  Coverage also depends upon a stated reliability.  An example is where it is a requirement that the desired level of signal is present at least 95% of the time.
- D -
Digital -
  • Digital technology, unlike analog, breaks your voice signal into binary codes – a series of “1”s and “0”s – and transfers it to the other end where another device takes all the numbers and reassembles them into the original signal.  The beauty of digital is that it knows what it should be when it reaches the end of the transmission.  That way, it can correct any errors that may have occurred in the data transfer.  In most cases, this means you’ll get distortion-free conversations. The nature of digital technology allows it to cram lots of those “1”s and “0”s together in the same space an analog signal uses.  Like any new technology, digital is still relatively expensive.
Drop & Swap Site -
  • What happened when a building at a site needs replacing with something new, usually a pre-fabricated structure. This happens when a building operated by a partner isn't sufficient for the project's needs. (Scope Level 2).

E - H

- E, F -
 

- G -
Gateway Switch -
  • One solution to interoperability is the Gateway Switch device, also called an audio matrix or cross band switch, that links different radio systems. Not unlike a dispatcher’s patch panel, the Gateway Switch device simply passes base band audio signals from the receiver portion of one radio to the transmitter portion of a another radio system. An advantage of the Gateway Switch device over the dispatcher’s patch panel is that it requires no manual intervention once configured.
     
    The Gateway Switch device automatically routes voice calls from one radio system to another in response to the linking of icons on a computer screen. It will also allow a connection between radios and telephones or cellular phones, or vise versa. In addition, the Gateway Switch has a degree of versatility that is not available via the dispatch patch panel.
     
    The Gateway Switch device can be configured either in a fixed location or in a mobile platform that can be mounted in a van, sports utility vehicle or command vehicle. In a transportable mode, the Gateway Switch device becomes a mobile repeater, allowing different radio systems to communicate in a wide geographical radius around an incident.
Greenfield Site -
  • A completely undeveloped site, without any of the necessary services. A greenfield site is the last option. (Scope Level 3).

- H -
Hertz -
  • Radio frequency spectrum is measured in hertz (Hz). Radio frequency is the portion of electromagnetic spectrum that carries radio waves. The distance an energy wave takes to complete one cycle is its wavelength. Frequency is the number of wavelengths in a given amount of time. One cycle in one second is one hertz. Radio frequency radiation is usually measured in kilohertz (kHz), megahertz (MHz) or gigahertz (GHz). One million cycles in one second is one megahertz, or 1 MHz.

I - L

- I -
Inactive Site -
  • Potential backbone or spur sites that have been fully assessed and found inadequate for various reasons. (Scope Level 4).
Infrastructure -
  • The underlying, permanent installations required for radio communications. Infrastructure includes antennas, base/repeater stations, consoles, links (fiber, microwave, radio and wire), power supplies and the support structure, such as secure buildings and towers.
Interoperability -
  • In general, interoperability refers to the ability of emergency responders to communicate seamlessly with other systems or products without any special effort. Wireless communications interoperability specifically refers to the ability of emergency response officials to share information via voice and data signals on demand, in real time, when needed and as authorized. For example, when communications systems are interoperable, police and firefighters responding to a routine incident can talk to each other to coordinate their efforts.
     
    Communications interoperability also makes it possible for emergency response agencies responding to catastrophic accidents or disasters to work effectively together. Finally, it allows emergency response personnel to maximize resources in planning for major predictable events such as the Olympic Trials or an inauguration, or for disaster relief and recovery efforts.
Interoperability Channels -
  • The Federal Communications Commission (FCC) has designated several frequencies as primary status for interoperable communications within the Very High Frequency (VHF), Ultra High Frequency (UHF), 700 MHz, and 800 MHz bands. These frequencies can be used on a non-routine basis for interoperable communications between any local or state entity. Additionally, these channels can be used across interstate borders with neighboring public safety jurisdictions. Channels designated for nationwide interoperability are:
    Frequency (MHz)
    Use
    Label
    Description
    155.7525
    Base Transmit
    VCALL
    VHF Calling Channel
    151.1375
    Base Transmit
    VTAC 1
    VHF Tactical Channel no. 1
    154.4525
    Base Transmit
    VTAC 2
    VHF Tactical Channel no. 2
    157.7375
    Base Transmit
    VTAC 3
    VHF Tactical Channel no. 3
    159.4725
    Base Transmit
    VTAC 4
    VHF Tactical Channel no. 4
    453.2125
    Base Transmit
    UCALL
    UHF Calling Channel
    453.4625
    Base Transmit
    UTAC 1
    UHF Tactical Channel no. 1
    453.7215
    Base Transmit
    UTAC 2
    UHF Tactical Channel no. 2
    453.8625
    Base Transmit
    UTAC 3
    UHF Tactical Channel no. 3
    764-806 MHz
    I/O Sub-Band
     
     
    821.0125
    Base Transmit
    ICALL
    NPSPAC Calling Channel
    821.5215
    Base Transmit
    ITAC 1
    NPSPAC Tactical Channel no. 1
    822.0125
    Base Transmit
    ITAC 2
    NPSPAC Tactical Channel no. 2
    822.5125
    Base Transmit
    ITAC 3
    NPSPAC Tactical Channel no. 3
    823.0125
    Base Transmit
    ITAC 4
    NPSPAC Tactical Channel no. 4
Interoperability Challenges -
  • There are still many issues that need to be addressed to achieve interoperability among first responders. Five key issues underline the current status of interoperability among public safety agencies throughout the country:
    • incompatible and aging communications equipment;
    • limited and fragmented funding;
    • limited and fragmented planning
    • a lack of coordination and cooperation; and
    • inadequate and fragmented radio spectrum.
Interoperability Continuum -
  • This term refers to a tool designed by the U.S. Department of Homeland Security’s SAFECOM group for improving emergency response communications and interoperability. The elements of the continuum include governance, standard operating procedures, technology, training and exercises, and use of interoperable communications.
Interoperability Levels -
  • There are six levels of interoperability that represent the most common communications solutions public safety agencies and departments consider for implementation. Most are not mutually exclusive. Departments may selection more than one to meet various interoperability requirements. The six levels of interoperability are: 
    • swap radios,
    • talk-around,
    • mutual aid channels,
    • gateways or console patches,
    • system-specific roaming; and
    • standards-based shared systems.

- J, K -
 

- L -
Loop -
  • A subsection of the microwave system. Within that system there is a series of microwave links and sites that are arranged in a loop configuration so that information can be sent in either direction. If there's a failure in the loop, the information flow is reversed so it gets to its destination despite the failure.

M - P

- M -
Microwave -
  • In the State Radio Project system, microwave is used to transmit radio signals from site to site.

- N -
Narrowband (Narrow Bandwidth) -
  • This refers to a signal that occupies only a small amount of space of the radio spectrum – the opposite of broadband or wideband. Narrowband is a transmission medium or channel with a single voice channel.
Narrowbanding Requirement -
  • This is the term used to refer to the Federal Communications Commission (FCC) requirement that – on or before January 1, 2013 – all public safety agencies must migrate their 25 kHz wide operating systems below 512 MHz to 12.5 kHz narrowband channels.  The FCC’s order will affect planning, new equipment purchases and new systems procured in the timeframe leading up to that date. Any equipment that is not capable of operating on channels of 12.5 kHz or less will need to be replaced. It is important to note that the FCC actually divided the frequencies into 6.25 kHz channels. They are allowing narrowbanding to 12.5 kHz as an interim step and they have not decided on the date to move to 6.25 kHz.
NIIX -
  • Provides a centralized, secure warehouse for information related to interoperable communications.
NPSTC -
  • A federation of organizations whose mission is to improve public safety communications and interoperability through collaborative leadership.

- O -
OEC -
  • The Office of Emergency Communications is SAFECOM’s development of guidance, tools and templates. OEC is managed by the Directorate for National Protection and Programs.
OIC -
  • The Office for Interoperability and Compatibility supports SAFECOM’s related research, development, testing evaluation and standards. OIC is managed by the Science and Technology Directorate.
Operability -
  • Communication operability is the ability to communicate effectively on one’s own radio communication system. Before interoperability can be achieved, agencies must have a system that can support and maintain operability.

-  P -
Preconstruction Phase -
  • This phase indicates work that is done primarily to construction of towers, shelters and site infrastructure.
Project 25 -
  • Project 25 (P-25) is an established standard designed to ensure that communications equipment is manufactured to meet the interoperable needs of the public safety community. Developed in North America under the guidance of local, state and federal representatives, P-25 is gaining worldwide acceptance for public safety, security, public services and commercial applications. The published P-25 standards suite is administered by the Telecommunications Industry Association (TIA). Radio equipment that demonstrates compliance with P-25 is able to meet a set of minimum requirements to fulfill the needs of public safety. These include the ability to interoperate with other P-25 equipment so that users on different systems can talk via direct radio contact. The P-25 standard was created by and for public safety professionals. From the beginning, P-25 has targeted four primary objectives:
    • Allow effective, efficient and reliable intra-agency and inter-agency communications so organizations can easily implement interoperable and seamless joint-communications in both routine and emergency circumstances.
    • Ensure competition in system life cycle procurements so agencies can choose from multiple vendors and products, ultimately saving money and gaining the freedom to select from the widest range of equipment and features.
    • Provide user-friendly equipment so users can take full advantage of their radios’ lifesaving capabilities on the job – even under adverse conditions – with minimal training.
    • Improve radio spectrum efficiency so networks will have enough capacity to handle calls and allow room for growth, even in areas where the spectrum is crowded and it is difficult for agencies to obtain licenses for additional radio frequencies.
PSWN -
  • Public Safety Wireless Network is the program that brings together officials from local, state, federal and tribal governments to improve wireless interoperability among the nation’s fire, law enforcement and emergency medical services organizations. The program conducts pilot information on wireless interoperability.

Q - T

- Q -
 
R -
Radio Phase -
  • Installation of the radio system at each site is the final step before the site goes active. The radio system installation completes the process that began with site surveys. Radio cannot be installed until the microwave has been installed.
Radio Frequency (RF) -
  • Radio frequency refers to the portion of the spectrum in which electromagnetic waves can be generated by alternating the current feed to an antenna. For purposes of our interoperability discussions, public safety radio systems operate in different radio frequency bands, much like the AM and FM bands of your standard radio. Just as an AM radio cannot pick up an FM radio station, public safety radios in one frequency band cannot pick up transmissions in another frequency band. Wireless technology requires radio frequency capacity in order to function.
Radio Repeater -
  • A radio repeater is the combination of a radio receiver and transmitter that receives a weak or low-level signal and re-transmits it at a higher level or higher power allowing the signal to cover longer distances without degradation. In emergency services communications, repeaters are used extensively to relay radio signals across a wider area. With most emergency dispatch systems, the repeater is synonymous with the base station, which performs both functions.
Radio Spectrum -
  • Radio spectrum refers to the array of channels available for communications. Spectrum is the highway over which voice, data and image communications travel. It is electronic real estate. Radio spectrum is finite; what exists today is all there ever will be, making it one of our nation’s most valuable resources. Public safety shares radio spectrum with television and radio broadcasters, government users and other communication consumers who require spectrum for everything from garage door openers to cell phones.
     
    There is a limited and fragmented amount of radio spectrum available for public safety. The Federal Communications Commission (FCC) has allocated certain frequencies to public safety, but it is inadequate and scattered in separate bands across the spectrum, making in difficult for different agencies and jurisdictions to communicate.
     
    The fragmentation of spectrum assignments for public safety is a significant barrier to achieving interoperability in the future. In the past it has been the source of many of the technical problems that have plagued public safety communications, such as out-of-date equipment, proprietary solutions, congestion and interference.
Radio Wave -
  • Radio waves are the basic building block of radio communications. Like waves on a pond, a radio wave is a series of repeating peaks and valleys. The entire pattern of a wave, before it repeats itself, is called a cycle. The number of cycles, or times that a wave repeats in a second, is called frequency. Frequency is measured in the unit hertz (Hz), referring to a number of cycles per second. One thousand hertz is referred to as a kilohertz (kHz), one million hertz as a megahertz (MHz), and one billion hertz as a gigahertz (GHz).

- S -
SAFECOM -
  • This is the umbrella program within the federal government that oversees initiatives and projects pertaining to public safety communications and interoperability. The program is managed by the U.S. Department of Homeland Security.
Shelter -
  • Each shelter contains racks of radio equipment, microwave equipment, batteries and power supplies. Depending on the site, the shelter may contain voice radio system equipment, data radio system equipment and/or interoperability radio system equipment. Shelters are built to exacting specifications that ensure their ability to withstand wind, snow loads, earthquakes and assault by firearms.
Simplex -
  • Simplex refers to sending information in one direction at a time. Simplex can refer to car-to-car, and/or it can refer to base to mobile. Simplex means that only one person can transmit at a time. (Duplex, for example, is typified by use of a telephone where both parties can speak at once.) One common simplex mode is referred to as “talk-around” or direct mode.
     
    The significant drawback to talk-around is that it only provides radio coverage in a very limited area, such as one city block. While this is inefficient for dispatch operations, talk-around operations are used extensively for fire ground crews and often for law enforcement special operations, where in-building signal penetration or operational security is critically important.
Spectrum -
  • See Radio Spectrum.
Spur Site -
  • Spur sites are used for public safety radio communications but are not within one of the project's loops of backbone sites. Spur sites have about one-third of the bandwidth of a backbone site. A spur site houses voice and/or mobile data radio transmission equipment. Voice or data signals first transmitted to a spur site are then carried to a backbone site to become part of the loop that backbone site provides. If a spur site is for any reason disabled, the connectivity to the backbone loop will be lost.
System of Systems -
  • In its simplest form, “system of systems” means the use of technology gateways to allow the connection of otherwise incompatible public safety communications systems. This approach builds both on existing and future systems. In June 2005, the Oregon SIEC adopted a policy to promote and support a “system of systems” approach in Oregon.

 - T -
TOPOFF -
  • The nation’s premier terrorism preparedness exercise, involving top officials at every level of government as well as representatives from the international community and private sector. Thousands of federal, state, territorial and local officials engage in various activities as part of a robust, full-scale simulated response to a multi-faceted threat.
Trunked Radio System -
  • A trunked radio system is used to maximize available capacity in a two-way radio system.  Trunking works by using a computer to assign users to a limited number of transmitters.  This is possible because not everyone in a group talks at once and radio transmissions are usually short. An example is that in non-trunked use, four independent transmitters used by independent groups each carry a single talk path. Users of each talk path do not have routine access to the other transmitters on the site. If those same four transmitters were trunked, the effect is though there were perhaps ten virtual talk paths. Users are divvied into logical “talk-groups” and the computer aligns all of a talk group’s users onto an assigned channel.
     
    Trunking relies on the use of a constant control channel that is a full time bit stream sent over an area to and from users and the system computer. The computer keeps track of who is on the air and who is selected to each talk group. When a user wants to talk to his/her group, the users’ radio sends data packets to a computer, operating on a dedicated frequency (control channel) to request communication on a specific talk group. The controller sends a digital signal to all radios monitoring that talk group, instructing the radios to automatically switch to the frequency indicated by the system to monitor the transmission. After the user is done speaking, the users’ radios return to monitoring the control channel for additional transmissions.
     
    This arrangement allows multiple groups of users to share a small set of actual radio frequencies without hearing each other’s conversations. Trunked systems primarily conserve limited radio frequencies and also provide other advanced features to users.
     
    “Trunked” systems differ from “conventional” systems in that a conventional radio system uses a dedicated channel (frequency) for each individual group of users, while “trunking” radio systems use a pool of channels which are available for a great many different groups of users.
     
    For example, if police communications are configured in such a way that twelve conventional channels are required to permit citywide dispatch based upon geographical patrol areas, during periods of slow dispatch activity much of that channel capacity is idle.  In a trunked system, the police units in a given geographical area are not assigned a dedicated channel, but instead are members of a talk-group entitled to draw upon the common resources of a pool of channels. In this example, seven trunked channels could probably handle the traffic load previously used by the 12 conventional channels.
     
    Trunked radio takes advantage of the probability that in any given number of user units, not everyone will need channel access at the same time. Therefore with a given number of users, fewer discrete radio channels are required. From another perspective, with a given number of radio channels, a much greater number of user groups can be accommodated.  In the example of the police department, this additional capacity could then be used to assign individual talk-groups to specialized traffic, investigative or special event groups who might otherwise not have the benefit of individual private communications.

U - Z

- U, V -
Undefined Site -
  • A site under construction for the project's use that has not yet been evaluated for the availability of services, such as roads, power or buildings. (Scope Level 0).

W, X, Y, Z -
Wave -
  • See Radio Wave.