Terminology 700 MHz: A radio, system or channel that operates within the range of the 794- 815 MHz. These systems may be conventional or trunked. 800 MHz: A radio, system or channel that operates within the range of the 839- 860 MHz. These systems may be conventional or trunked. A Amplification: The process of increasing the strength of a radio signal. APCO: Association of Public Safety Communications Officials, www.apco911.org B Backward compatibility: Ability of new units to operate within an "old" system infrastructure or to directly intercommunicate with an "old" unit. Band Plan: A plan to allocate different frequencies within a range for specific purposes and users. C Cache radios: A spare set of radios maintained as a shared regional resource; the radios are fully charged, include extra batteries and chargers, and are labeled with the owner agency name, frequencies, band and system. These radios are typically programmed with a set of interoperability channels or talkgroups. Call Sign: A group of letters and numbers used to identify a station and the country authorizing its operation. The Federal Communications Commission (FCC) assigns Call Signs to each station. Calling Frequency: An agreed-upon frequency where stations attempt to contact each other; once contact is made, stations move to a working frequency. Also known as a "hailing frequency". Car to car: To communicate with another station without using a repeater. To transmit and receive on the same frequency. Also referred to as direct or simplex. Carrier: The un modulated output of a radio transmitter. CB: Citizens’ Band radio Channel Integrator: A sophisticated, process/device or system which takes several inbound radio signals from a variety of bands and electronically interconnects them on the “outbound side” to one or more other otherwise incompatible radio channels. Examples: JPS ACU-1000 switch and Ma/Com’s “Network First” switch Channel: The frequency on which a radio transmission takes place, or the input and output frequency pair used by a repeater station. May also refer to the assigned number on the radio selector knob of the mobile or portable radio. Co-channel Interference: Interference from stations on frequencies adjacent to the desired signal. Console Patch: Buttons or icons in the dispatcher’s radio console that (when properly selected) permit the ability to “patch” or connect two dissimilar regular radio channels or “trunked radio talkgroup” together for a specific conversation. (Example: Patching the VHF Fire Channel to the UHF Street Department Channel) Control Point: The physical location from which a radio station’s functions (setting frequency, turning the station off and on, etc.) are controlled. COTS: Software and hardware products that are ready-made and available for sale to the general public. COTS products are typically installed in existing systems and do not require customization. Cross Band Repeater: A single device which receives inbound radio traffic on one channel in one band (say MINSEF on VHF @ 155.475 MHz) and rebroadcasts it out on another channel in another band (say NPSPAC InterOp Channel 1 at 866.0125 MHz) and vice-versa D Dead Zone: A region where a radio signal cannot be received due to propagation difficulties. Digital & Analog: The methods of modulating a radio signal as it travels through the air. Example: Digital signals are the speaker’s words turned into a series of 1’s and 0’s, which are then transmitted through the air, received at the other end and then reconstituted back into the audio sounds of the speaker’s words. The translation process is done by a device called a "vocoder". Analog signals are the speaker’s words translated into wave forms and the wave forms are then sent through the air and can be heard through a loudspeaker at the receiving end. Generally, analog wave forms require a wider radio channel bandwidth than a digital transmission carrying the same sound, but digitally. Direct: To communicate with another station without using a repeater. To transmit and receive on the same frequency. Also referred to as simplex; or car to car. DTRS: Digital Trunked Radio System. Colorado operates a statewide DTRS radio network providing service to federal, state, and local agencies. The system operates in the 700/800 MHz band. Duplex: To transmit on one frequency while listening for replies on another. E EDACS: Enhanced Digital Access Communications System. The 10 county metropolitan area around the City and County of Denver operate using several interconnected EDACS radio networks. This system operates in the 800 MHz band. Encryption: In digital radio systems, all radio transmissions are “digitized” (broken down into a formatted series of 1’os and 0’s according to some logic mutually known to all radios on that system) at a minimal, standards based level. In an “encrypted” system, these digital bits are re-coded one again based on a secret code known only to the radios within the system that have been programmed with that same secret code. In older analog radio systems, if encryption was employed, analog voice sounds were digitized, and then sent over the analog channel as an analog wave form to the distant radio, which had to have the similar decryption program in it to unscramble what the transmitting radio sent. This technique dramatically reduced the effective range of the otherwise analog signal, whereas with modern encryption employed over already digital systems, there is no degradation in signal quality or range. F FCC: Federal Communications Commission Fixed gateways: A device which is used to connect channels and/or talkgroups from disparate radio systems together. A fixed gateway is one permanently installed within the radio system infrastructure. The NetworkFirst Gateway serving the Denver metro area is an example of a Fixed Gateway. Frequency: A defined unit of electromagnetic spectrum expressed as the exact location of the assigned channel in the spectrum. For example, the Fire Emergency Radio Network (FERN) operates on Frequency 154.2800 MHz. FRS: Family Radio Service; radio frequencies that do not need an individual license. FRS radios have shared frequencies and short range. G Gateways: : A device which is used to connect channels and/or talkgroups from disparate radio systems together. Gateways may either be "fixed" (permanently installed within the radio system infrastructure) or "mobile" (which can be brought to an incident scene). Dispatch Center radio consoles can also "patch" channels and talkgroups together and are sometimes also referred to as console gateways. Gain: The apparent increase in the strength of a signal radiated or received by an antenna caused by the antenna having better performance in some directions than others. Gigahertz: Unit equal to 1000 megahertz or 1,000,000 kilohertz GPS: Global Positioning System Ground: A connection to a point of zero voltage, like the Earth. H Hard Patch: A system whereby a dedicated radio is installed to take what it hears and always patch it over to another radio system channel or talk group, and (sometimes) vice-versa. (Example: The Street Department’s UHF radio channel is “hard patched” to a talk group in the police department’s trunked radio system which could be called “streets”). Hertz: One complete cycle of a radio wave per second. High VHF: 150-174 MHz I IP: Internet Protocol Input Frequency: The frequency on which a repeater station listens for signals to retransmit. Intermod: Short for "intermodulation," this means false or spurious signals produced by two or more signals mixing in a receiver or repeater station. ISSI: Inter-RF Subsystem Interface K Kilohertz: Unit equal to 1000 hertz. Kilowatt: Unit equal to 1000 watts of transmitter power. L LMR: Land Mobile Radio Low Band: A system or channel that operates in the 39-45 MHz band. Low UHF: 450-470 MHz Low VHF: 30-50 MHz M Megahertz: Unit equal to 1,000,000 hertz or 1000 kilohertz. Microwave: A “point to point” radio system that transmits signals (often data) from one fixed point (microwave dish) direct, in a line of sight mode, to another fixed point. Often microwave is implemented to “bypass” expensive, monthly recurring costs for “data lines” leased from the phone company. Mobile Gateways: portable interconnect switches that connect two or more disparate radio systems. Mobile Station: A two-way radio unit installed in a car, boat, plane, etc., and used while in motion or at various stops. Multiband Antenna: An antenna suitable for operation on several different bands of frequencies N Narrowbanding: Starting in 2013, all radio systems operating below 512 MHz must be narrow band compliant. Splits a 25 KHz wide channel into two separate 12.5 kHz wide channels. When technology permits, another migration will occur down to 6.25 Khz channels. Most agencies in Colorado have already completed the first migration to 12.5 Khz. NPSPAC: A radio, system or channel that operates in the 800-815 & 845-860 MHz bands. NPSPAC stands for "National Public Safety Planning Advisory Committee". NPSPAC channels operate under more stringent FCC rules regarding power output by base stations, so as to permit more channel re-use across a geographic area such as a state. NPSTC: National Public Safety Telecommunication Council O OEC: Office of Emergency Communications, a division of the Department of Homeland Security. Omnidirectional Antenna: An antenna that transmits and receives equally well in all directions. Output Frequency: The frequency on which the base station radio or repeater transmits the voice or data signal to another radio user or device. P P25: APCO Project-25 Digital Standard, also referred to as Common Air Interface (CAI). APCO Project 25, or "P-25" for short, is the public safety industry standard developed by the APCO International (Association of Public Safety Communications Officials) to provide a radio solution that would allow different agencies using different radio systems to interoperate according to a public safety industry standard and not by system manufacturer.