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					Alpha Communications® GLOSSARY OF TERMS

                            Term                                                                   Description
                               A                         A symbol designation for ampere.

                              AC                         Alternating current.
                                                         The capability for one or more intercom stations to place an intercom call to all of the other stations
                            All-Call                     on the system (capable of receiving an all-call) simultaneously.
                                                         A standard for expressing wire diameter. As the AWG number gets smaller, the wire diameter gets
                American Wire Gauge (AWG)                larger.
                                                         A standard unit of electrical current. Defined as the amount of current that flows when one volt of
                        Amp (Ampere)                     electromotive force is applied across one ohm of resistance.
                                                         The activation of a lighted or mechanical indictor (annunciator) when a remote switch or device has
                        Annunciation                     been activated.
                                                         A device that indicates by a lighted or mechanical indictor, when a remote switch or device has
                         Annunciator                     been activated.
                             ANSI                        American National Standards Institute. Usually used to define hardware or electrical standards.
                                                         The decrease in magnitude of a signal as it travels through any transmitting medium, such as a
                         Attenuation                     cable or circuitry. Attenuation is measured as the logarithm of a ratio. It is expressed in decibels or
                                                         A term used to describe sounds within the range of human hearing. Also used to describe devices
                            Audio                        which are designed to operate usually within this range (20 Hz to 20 kHz).
                      Audio Frequency                    Frequencies within the range of human hearing: approximately 20 to 20,000 Hz.
                                                         American Wire Gauge. A wire diameter specification. The smaller the AWG number, the larger the
                             AWG                         wire diameter.
                                                         A cable having two identical conductors which carry voltages opposite in polarity and equal in
                        Balanced Line                    magnitude with respect to ground, suitable for differential signal transmission.
                                                         The difference between the upper and lower limits of a given band of frequencies. Expressed in
                          Bandwidth                      Hertz.
                             Baud                        Unit of data transmission speed meaning bits per second (300 baud=300 bits per second).

                              Bit                        One binary digit (0 or 1). Eight (8) bits equals one (1) byte.
                                                         The number of binary bits that can be transmitted per second - I.e. Mbps (Mega - millions), Gbps
                       Bits Per Second                   (Giga - billions).
                                                         Abbreviation for "Bayonet Neil Concelman". A twist-lock coaxial cable connector used extensively in
                             BNC                         video and Radio Frequency applications. It is named for its inventor.
                                                         A device or amplifier inserted into a line or cable to increase the voltage. Transformers may be
                           Booster                       employed to boost ac voltages.
                                                         The number of binary bits that can be transmitted per second - I.e. Mbps (Mega - millions), Gbps
                             BPS                         (Giga - billions).
                                                         A group of textile or metallic filaments interwoven to form a tubular flexible structure which may be
                             Braid                       applied over one or more wires, or flattened to form a strap.
                               C                         Symbol designation for capacitance, and Celsius temperature measurement.

                            Cable                        A group of individually insulated conductors inside a common jacket.

              Canadian Electrical Code (CEC)             Canadian version of the US National Electrical Code (NEC).
                                                         The ability of a dielectric material between conductors to store energy when a difference of potential
                         Capacitance                     exists between the conductors. The unit of measurement is the farad. Cable capacitance is usually
                                                         measured in picofarads (pF).
                                                         Cable crosstalk or interference resulting from the coupling of the electrostatic field of one conductor
                    Capacitive Crosstalk                 upon one or more others.
                                                         An electronic component consisting of two conducting surfaces separated by a dielectric material.
                          Capacitor                      The capacitance is determined by the area of the surfaces, type of dielectric, and spacing between
                                                         the conducting surfaces.
                            CATV                         Abbreviation for Community Antenna Television (aka Cable TV).

                            CCTV                         Closed-circuit television (video).

                            Circuit                      A network of conducting media designed to pass an electric current. (1 of 7) [8/31/2001 9:54:17 AM]
Alpha Communications® GLOSSARY OF TERMS
                                                         A cylindrical transmission line consisting of a conductor centered inside a metallic tube or shield,
                    Coaxial Cable (Coax)                 separated by a dielectric material, and usually covered by an insulating jacket. Usually used to
                                                         transmit video signals.
                                                         A term used to indicate the highest medical emergency situation in a hospital or health care facility.
                          Code Blue                      It is derived from the concept of a person turning 'Blue' from lack of oxygen or another emergency.
                                                         It is also called Code Call or Code 99.
                          Coil Cord                      A cord having specially treated insulation or jacket so that it will retract like a spring.
                                                         A system of different colors or stripes used to identify components of cables such as individual
                         Color Code                      conductors or groups of conductors.
                                                         An intercom system using handset type stations where anyone handset that is lifted off of its cradle
                        Common Talk                      is connected to a common talk (party line) circuit, without privacy. A Common Talk circuit usually
                                                         allows for conference call capabilities as well.
                                                         Refers to one or more wires that are run in parallel (in common) to multiple intercom or
                       Common Wires                      video-intercom stations. Usually refers to the main (trunk) power or control wires on a system.
                                                         The encoded output of a camera, video tape recorder, etc., whereby the red, green, blue, horizontal
                      Composite Video                    and vertical sync are transmitted simultaneously down one cable.
                          Conductor                      A substance, usually metal, used to transfer electrical energy from one point to another.
                                                         A tube of metal or plastic through which wire or cable can be run. Used to protect the wire or cable
                           Conduit                       and, in the case of metal conduit, make it fireproof and to minimize interference.
                                                         A mechanical device designed to allow electrical flow from one wire or cable to a device on another
                          Connector                      cable.
                             Cord                        A very flexible insulated cable or string.
                                                         Central Processing Equipment. Usually refers to a computerized central control unit uusing
                             CPE                         microprocessor or microcontroller circuitry.
                             CPS                         Abbreviation for cycles per second (or Hertz). Frequency.
                                                         Central Processing Unit. Usually refers to a computerized central control unit uusing
                             CPU                         microprocessor or microcontroller circuitry.
                                                         A type of interference caused by audio frequencies from one pair of conductors being coupled into
                          Crosstalk                      adjacent pairs.
                             CRT                         Cathode Ray Tube. A conventional TV (video) screen.
                                                         Abbreviation for Canadian Standards Association, the Canadian version of the Underwriters
                             CSA                         Laboratories (UL).
                              dB                         Decibel. A unit of measure of sound level.

                              DC                         Direct current.
                                                         Decibels are also used to express acoustic power, such as the apparent level of a sound. The
                         Decibel (dB)                    decibel can express an actual level only when comparing with some definite reference level that is
                                                         assumed to be zero dB.
                                                         A method to allow a station to sit on, or mount to a desktop or tabletop, usually using a sloped
                       Desk Mount(ing)                   cabinet or housing.
                          Dielectric                     An insulating (non-conducting) medium when used in a signal-carrying design.

                        Digital Signal                   An electrical signal which possesses two distinct states (on/off, positive/negative).

                          Distortion                     Any undesired change in a wave form or signal.

                          Distortion                     Any undesired change in a wave form or signal.

                        Door Opener                      An electro mechanical device used to electrically unlock or release a door which has been signaled
                                                         electrically from a remote location.
                        Door Release                     See Door Opener.

                         Door Strike                     See Door Opener.

                             Earth                       British terminology for zero-reference ground.

                              EIA                        Electronic Industries Association (formerly RMA or RETMA).
                                                         Referring to the combined electric and magnetic fields caused by electron motion through
                       Electromagnetic                   conductors.
                 Electromagnetic Coupling                The transfer of energy by means of a varying magnetic field. Inductive coupling.

                         Electrostatic                   Pertaining to static electricity, or electricity at rest. An electric charge, for example.

                             EMI                         Abbreviation for electromagnetic interference.

                             EMT                         Electro-metallic tubing. A form of metallic pipe or conduit.

                               f                         Frequency.
                                                         Usually used to refer to a type of door opener. When power is 'OFF', the device is unlocked or
                           Fail Safe                     unlatched.
                                                         Usually used to refer to a type of door opener. When power is 'OFF', the device is locked or latched
                         Fail Secure                     (or secure).
                                                         A unit of capacity that will store one coulomb of electrical charge when one volt of electrical
                            Farad                        pressure is applied.
                                                         An overload to an audio circuit usually caused by the audio output being too close to the audio
                          Feedback                       input.
                         Fiber Optics                    Light transmission through optical fibers for communication and signaling.

                      Flame Resistance                   The ability of a material not to fuel a flame once the source of heat is removed. (2 of 7) [8/31/2001 9:54:17 AM]
Alpha Communications® GLOSSARY OF TERMS
                                                         Also referred to as planar and/or ribbon cable. Any cable with two or more parallel conductors in the
                          Flat Cable                     same plane encapsulated by insulating material.
                           Floating                      Referring to a circuit which has no connection to ground.
                                                         Usually refers to making a cut-out or opening in the wall to allow the internal components (guts) of a
                      Flush Mount(ing)                   station to fit inside the finished wall.
                              FM                         Frequency modulation. Usually refers to a range of radio frequencies.

                          Frequency                      The number of times a periodic action occurs in one second. Measured in Hertz.
                                                         The characteristic of a device denoting the range of frequencies over which it may be used
                    Frequency Response                   effectively (i.e. 20 to 20,000 Hz).
                                                         The physical diameter of a wire. A standard for expressing wire diameter. As the AWG number gets
                            Gauge                        smaller, the wire diameter gets larger.
                             Giga                        One billion.

                       Gigahertz (GHz)                   A unit of frequency equal to one billion hertz.

                             GND                         Ground or Electrical Ground.
                                                         An electrical connection between a circuit and the earth. Also refers to a conductor connected to
                           Ground                        earth. In some instances, can refer to a central metallic point designated as having "zero" potential.
                     Ground Conductor                    A conductor in a transmission cable or line that is grounded.
                                                         An undesirable circuit condition in which interference is created by ground currents when grounds
                        Ground Loop                      are connected at more than one point.
                                                         The potential of the earth. A circuit, terminal, or chassis is said to be at ground potential when it is
                      Ground Potential                   used as a reference point for other potentials in the system.
                                                         Ability to reply to a voice call from an intercom station, without having to press any buttons or
                      Hands-Free Reply                   controls.
                                                         A group of cables, usually with many breakouts with the wire ends prepared for termination or
                           Harness                       terminated to connectors and ready to install.
                                                         The number of changes in polarity which a signal makes in one second. An indication of frequency.
                          Hertz (Hz)                     Also referred to as cycles-per-second.
                      Home Run Wires                     See Selective Wires.
                                                         Multi unit mailboxes with deep 'horizontal' doors/compartments. They are also referred to as
                   Horizontal Mailbox(es)                'pidgeon hole' mail boxes. Horizontal mailboxes take up a less wall space (width), but they require a
                                                         wall depth of up to 18". They are usually used in larger buildings.
                                                         A term used to describe the 60- or 120 cycle per second noise present in the sound of some
                             Hum                         communications equipment. Usually hum is the result of undesired coupling to a 60 cycle source or
                                                         to the defective filtering of 120 cycle ripple output of a rectifier.
                                                         The resistance that a circuit offers to the flow of alternating current or any other varying current at a
                         Impedance                       particular frequency. It is measured in ohms.
                      Impedance, High                    Generally, the area of 25,000 ohms or higher.

                       Impedance, Low                    Generally, the area of 1 through 600 ohms.
                                                         The property of wire which stores electrical current in a magnetic field around the wire. By coiling
                         Inductance                      wire, the effect can be intensified. It is measured in Henrys.
                                                         The phenomenon of a voltage, magnetic field, or electrostatic charge being produced in an object
                          Induction                      by lines of force from the source of such fields.
                     Inductive Crosstalk                 Crosstalk resulting from the coupling of the electromagnetic field of one conductor upon another.
                                                         A signal (or power) which is applied to a piece of electric apparatus or the terminals on the
                             Input                       apparatus to which a signal or power is applied.
                                                         A material having good dielectric properties which is used to separate close electrical components,
                          Insulation                     such as cable conductors and circuit components.
                           Interface                     The region where two systems or a major and a minor system meet and interact with each other.
                                                         Disturbances of an electrical or electromagnetic nature that introduce undesirable responses into
                         Interference                    other electronic equipment.
                             ISO                         International Standards Organization.

                           Isolation                     The ability of a circuit or component to reject interference, usually expressed in dB.

                            Jacket                       Pertaining to wire and cable, the outer protective covering (may also provide additional insulation).
                                                         A short length of conductor or flat cable used to make a connection between terminals or around a
                           Jumper                        break in a circuit, or between circuit boards.
                                                         A key keeper is basically a lock box into which a key to the building entrance door is stored. It
                                                         allows the building owner to comply with the USPS regulations requiring that the letter carrier be
                         Key Keeper                      allowed entry to a locked building lobby, without the need to bother any of the tenants. The letter
                                                         carrier uses his/her regular mailbox key to open the key keeper and retrieve the building key. Key
                                                         Keepers are also made with a pushbutton (instead of the key) to allow the letter carrier to
                                                         electrically release the building entrance door.
                             Kilo                        One thousand.
                                                         A data network connecting any number of users, intended to serve a small area. Local Area
                             LAN                         Network.
                            Laser                        A coherent source of light with a narrow beam and a narrow spectral bandwidth (about 2nm).
                                                         The length measured along the axis of a wire or cable required for a single strand (in stranded wire)
                                                         or conductor (in cable) to make one complete turn about the axis of the conductor or cable. In a
                             Lay                         twisted pair cable, the lay length is the distance it takes for the two wires to completely twist around
                                                         each other.
                           Leakage                       The undesirable passage of current over the surface of or through an insulator. (3 of 7) [8/31/2001 9:54:17 AM]
Alpha Communications® GLOSSARY OF TERMS
                                                         A semiconductor device that emits incoherent light formed by the P-N junction. Light intensity is
             Light Emitting Diode (LED Source)           roughly proportional to electrical current flow.
                                                         Refers to the output voltage level of a piece of electronic equipment. Usually expressed in decibels
                          Line Level                     (e.g.. 0dBv).
                         Line Voltage                    The value of the potential existing on a supply or power line.

                             Load                        A device that consumes power from a source and uses that power to perform a function.

                 Local Area Network (LAN)                A data network connecting any number of users, intended to serve a small area.
                                                         A method of running a cable with multiple conductors, looped (in parallel) from one location to the
                         Loop Wiring                     next.
                             Loss                        Energy or signal lost without accomplishing useful work.

                            Lossy                        Having poor efficiency.
                                                         A band of frequencies extending form 30 to 300 kHz in the radio spectrum, designated by the
                       Low Frequency                     Federal Communications Commission.
                                                         The portion of the composite video signal that represents the brightness or the black and white
                      Luminance Signal                   information.
                                                         Mutual inductance. The abbreviation for mega or 1 million. And also indicates 1000 (one thousand)
                              M                          feet in the wire industry. m=abbreviation for milli or one-thousandth.
                              mA                         milliampere (one-thousandth of an ampere).

                          Mag Lock                       An electro mechanical device used to hold a door closed, by means of an electro-magnet, until the
                                                         electrical power holding the door closed has been de-activated, usually from a remote location.
                        Magnetic Lock                    See Mag Lock.
                                                         An intercom station which typically can place a voice call to any other intercom station on the
                Master (a.k.a. Master Station)           system.
                            MATV                         Abbreviation for Master Antenna Television.

                            Mbps                         Mega bits per second - the number of bits, in millions, transmitted per second.

                             Mega                        Prefix meaning million.

                      Megahertz (MHz)                    Unit of frequency equal to one million hertz (one million hertz per second).

                             mFd                         Microfarad (one-millionth of a farad).

                            Micro                        Prefix meaning one-millionth.

                          Microfarad                     One-millionth of a farad (uf, ufd, mf, and mfd are common abbreviations).
                                                         Noise caused by mechanical excitation of a system component. In a single-conductor microphone
                        Microphonics                     cable, for example, microphonics can be caused by the shield rubbing against the dielectric as the
                                                         cable is flexed.
                              Mil                        A unit of length equal to one thousandth of an inch (.001").

                             Milli                       Prefix meaning one-thousandth.

                            Mode                         A single electromagnetic wave traveling in an optical fiber.
                                                         Device that converts signals in one form to another form compatible with another kind of equipment.
                           Modem                         Modulator/De-modulator.
                                                         Altering the characteristics of a carrier wave to convey information. Modulation techniques include
                         Modulation                      amplitude frequency, phase, plus many other forms of on-off digital coding.
                                                         A term usually used in the hardware industry to refer to a cutout in a piece of wood or metal made
                           Mortise                       in the shape of a projecting part shaped to fit the 'mortised' opening.
                           Multiplex                     A technique for putting two or more signals into a single channel.

                              mV                         Millivolt (one-thousandth of a volt).

                             mW                          Milliwatt (one-thousandth of a watt).

                            Mylar                        DuPont trademark for polyethylene terephtalate (polyester) film.

                             Nano                        One-billionth.
                                                         A publication of the National Fire Protection Association (NFPA) which outlines requirements for
               National Electrical Code (NEC)            electrical wiring and building construction. Also called the NEC.
                                                         A publication of the National Fire Protection Association (NFPA) which outlines requirements for
                             NEC                         electrical wiring and building construction. Also called the NEC.
                            NEMA                         National Electrical Manufacturers Association.

                           Network                       A network is a method of data communications between computers.

                            NFPA                         National Fire Protection Association.
                                                         In a cable or circuit, any extraneous signal which tends to interfere with the signal normally present
                            Noise                        in or passing through the system.
                         Non-Plenum                      Area that a cable can be installed in a building that is not used for air return.
                                                         The removal of the web section between conductors of a flat cable to aid in stripping, slitting, and
                            Notch                        termination.
                                                         Organization that formulated standards for the current American television system. Also describes
                                                         the system of color telecasting which is used in Japan, Thailand and parts of South America. NTSC
                            NTSC                         television uses a 3.579545 MHz subcarrier whose phase varies with the instantaneous hue of the
                                                         televised color and whose amplitude varies with the instantaneous saturation of the color. NTSC
                                                         employs 525 lines per frame, 30 frames per second and 59.94 fields per second. (4 of 7) [8/31/2001 9:54:17 AM]
Alpha Communications® GLOSSARY OF TERMS

                            Nylon                        An abrasion-resistant thermoplastic with good chemical resistance.
                                                         The unit of electrical resistance. The value of resistance through which a potential difference of one
                             Ohm                         volt will maintain a current of one ampere.
                            Output                       The useful power or signal delivered by a circuit or device.
                                                         PAL is a European color TV system featuring 625 lines per frame, 25 frames and 50 fields per
                                                         second. Used mainly in Europe, China, Malaysia, Australia, New Zealand, the Middle East, and
                 PAL (Phase Alternate Line)              parts of Africa. PAL-M is a Brazilian color TV system with 525 lnes per frame, 30 frames and 60
                                                         fields per second.
                                                         A circuit in which the identical voltage is presented to all components, with current dividing among
                       Parallel Circuit                  the components according to the resistances or the impedances of the components.
                                                         Digital information that is transmitted in parallel form. Often used informally to refer to parallel digital
                        Parallel Digital                 television signals.
                                                         A flexible piece of cable terminated at both ends with plugs. Used for interconnecting circuits on a
                          Patchcord                      patchboard.
                             Peak                        The maximum instantaneous value of a varying current or voltage.
                                                         Multi unit mailboxes mounted on a secure pedestal for outdoor use. Typically used in condominium
                    Pedestal Mailbox(es)                 and gated communities. The doors/compartments are similar to 'horizontal' style mailboxes. They
                                                         are also referred to as 'cluster' mailboxes or NDCBU's.
                            Phase                        An angular relationship between waves.

                         Phase Shift                     A change in the phase relationship between two alternating quantities.
                                                         Any device which is capable of transforming a measurable quantity of intelligence (such as sound)
                            Pickup                       into relative electrical signals (e.g., a microphone).
                             Pico                        One-trillionth.

                          Picofarad                      One billionth of a farad. A micromicrofarad. Abbreviation pF or mmF.
                                                         Also referred to as flat and/or ribbon cable. Any cable with two or more parallel conductors in the
                         Planar Cable                    same plane encapsulated by insulating material.
                                                         High polymeric substances, including both natural and synthetic products that are capable of
                            Plastic                      flowing under heat and pressure, called thermoplastics. Unlike rubber and other thermoset
                                                         compounds, plastics can be remelted and reused.
                                                         A compartment or chamber to which one or more air ducts are connected and that forms part of the
                           Plenum                        air distribution system.
                             Plug                        A male housing with male or female contacts.

                         Point Wires                     See Selective Wires.
                                                         The orientation of a flat cable or a rectangular connector. e.g., for gray flat cable, the colored edge
                         Polarization                    indicating the number one conductor.
                                                         A thermoplastic similar to polyethylene but stiffer and having a higher softening point (temperature).
                                                         This material is primarily used as an insulation material. Typically, it is harder than polyethylene.
                        Polypropylene                    This makes it suitable for thin wall insulations. The dielectric constant is 2.25 for solid and 1.55 for
                                                         cellular designs.
                                                         Broad class of polymers noted for good abrasion and solvent resistance. Can be in solid or cellular
                                                         form. This thermoplastic material is used primarily as a cable jacket material. It has excellent
                     Polyurethane (PUR)                  oxidation, oil, and ozone resistance. Some formulations also have good flame resistance. It is a
                                                         hard material with excellent abrasion resistance. It has outstanding "memory" properties, making it
                                                         an ideal jacket material for retractile cords.
                                                         A general purpose thermoplastic used for wire and cable insulation and jackets. Also known as
                      Polyvinyl chloride                 PVC.
                                                         Refers to equipment that has been submitted to the US Postal Service (USPS) and approved by the
                      Postal Approved                    USPS as having met certain USPS requirements and regulations.
                                                         An electro-mechanical switch built-into a piece of equipment that, when activated, electrically
                       Postal Release                    releases the door release mechanism at an entrance to a building to allow a USPS letter carrier to
                                                         gain access to the building.
                                                         The amount of work per unit of time. Usually expressed in watts and equal to the formula for power
                            Power                        in watts. (I to the second power times R).
                                                         The difference between the total power delivered to a circuit, cable, or device and the power
                         Power Loss                      delivered by that device to a load.
                         Power Ratio                     The ratio of power appearing at the load to the input power. Expressed in dB.
                                                         An intercom option that allows a station to be called, but the voice response is blocked unless the
                           Privacy                       recipient releases the privacy switch or function.
                                                         An electro-mechanical device which, when activated, makes and/or breaks an electrical connection.
                         Pushbutton                      Usually activated by a mechanical 'push' action.
                            Putup                        Packaging of finished wire or cable. Length of wire or cable on a spool or in a carton or box.

                             PVC                         Polyvinyl chloride. Sometimes referred to as vinyl. Fire resistant.

                             Quad                        A four conductor cable. Also called "star quad". Usually used in phone system wiring.

                              R-F                        Radio-frequency.

                    Radio Frequency (RF)                 Radio-frequency. Usually considered to be frequencies ranging from 1 MHz to 3GHz.
                                                         The maximum temperature at which an electric component can operate for extended periods
                     Rated Temperature                   without loss of its basic properties.
                                                         The maximum voltage at which an electric component can operate for extended periods without
                        Rated Voltage                    undue degradation or safety hazard.
                         Receptacle                      A female housing with male or female contacts.

                    Recessed Mount(ing)                  See flush mount(ing). (5 of 7) [8/31/2001 9:54:17 AM]
Alpha Communications® GLOSSARY OF TERMS

                           Rectifier                     An electronic component used to convert alternating current (AC) to direct current (DC).
                                                         The change in direction (or return) of waves striking a surface. For example, electromagnetic
                          Reflection                     energy reflections can occur at an impedance mismatch in a transmission line, causing standing
                                                         An intercom station which typically can answer a voice call from a master station. Remote stations
               Remote (a.k.a. Remote Station)            may be equipped with one or more call buttons for tone and/or visual signalling only to one or more
                                                         master stations. Also commonly referred to as ‘sub station’ or 'slave station'.
                           Repeater                      A receiver and transmitter combination used to regenerate an attenuated signal.
                                                         In dc circuits, the opposition a material offers to current flow, measured in ohms. In ac circuits,
                         Resistance                      resistance is the real component of impedance, and may be higher than the value measured at dc.
                                                         An ac circuit condition in which inductive and capacitive reactances interact to cause a minimum or
                         Resonance                       maximum circuit impedance.
                                                         A cord having specially treated insulation or jacket so that it will retract like a spring. Retractibility
                       Retractile Cord                   may be added to all or part of a cord's length.
                              RFI                        Abbreviation for Ratio Frequency Interference.
                                                         "RG" is the abbreviation for "radio guide," a military designation for a coaxial cable, and "U" stands
                             RG/U                        for "universal."
                                                         Abbreviation for the three parts of color video signal: red, green and blue, and also refers to
                             RGB                         multi-coaxial cables carrying these signals.
                                                         A flat cable made with parallel round conductors in the same plane. Also referred to as planar
                        Ribbon Cable                     and/or flat cable. Any cable with two or more parallel conductors in the same plane encapsulated by
                                                         insulating material.
                                                         A term usually used in the hardware industry to refer to a type of lock mechanism that fits into a
                        Rim (cylinder)                   latch mechanism that fits onto the surface of the door frame and is not cut-in.
                                                         The process of locating or identifying specific conductor paths by means of passing a current
                         Ringing Out                     through selected conductors.
                                                         A cable run used to connect a group of intercom or video-intercom stations. Most commonly
                             Riser                       referred to in apartment systems where cables are run in vertical risers/lines.
                                                         Telecommunications interface connector, consisting of 12 sets of phone contacts. Usually used in
                       RJ17C (RJ-17C)                    'No-Phone-Bill' or 'No-Phone-Line' type telephone entry systems.
                         RJ45 (RJ-45)                    Modular telecommunications connector, consisting of 8 contact points.
                                                         Ability to call a specific station (by voice and/or audible signal) by dialing a keypad or pressing the
                      Selective Calling                  station’s individual selector (call) button.
                                                         Refers to one or more wires that (typically) are run individually and directly from a remote station to
                       Selective Wires                   a master station that individually identifies that remote station or allows signaling or communication
                                                         directly with that remote station.
                                                         In wire industry terminology, a material possessing electrical conductivity that falls somewhere
                                                         between that of conductors and insulators. Usually made by adding carbon particles to an insulator.
                       Semiconductor                     Not the same as semiconductor materials such as silicon, germanium, etc. Used for making
                                                         transistors and diodes.
                                                         Pertaining to wire and cable, a layer of insulating material such as textile, paper, Mylar, etc., which
                                                         is placed between a conductor and it s dielectric, between a cable jacket and the components it
                          Separator                      covers, or between various components of a multiple-conductor cable. It can be utilized to improve
                                                         stripping qualities, flexibility, or can offer additional mechanical or electrical protection to the
                                                         components it separates.
                        Series Circuit                   A Circuit in which the components are arranged end to end to form a single path for current.

                            Sheath                       Pertaining to wire and cable, the outer protective covering (may also provide additional insulation).
                                                         A tape, serve or braid (usually copper, aluminum, or other conductive material) placed around or
                            Shield                       between electric circuits or cables or their components, to prevent signal leakage or interference.
                       Shield Coverage                   The optical percentage of a cable actually covered by shielding material.
                                                         The relative ability of a shield to screen out undesirable interference. Frequently confused with the
                    Shield Effectiveness                 term shield coverage.
                      Shield Percentage                  The percentage of physical area of a circuit or cable actually covered by shielding material.
                                                         Any visible or audible indication which can convey information. Also, the information conveyed
                            Signal                       through a communication system.
                      Signal Conductor                   A conductor in a transmission cable or line that carries electrical signals.
                                                         General Electric trademark for a material made from silicone and oxygen. Can be in thermosetting
                                                         elastomer or liquid form. The thermosetting elastomer form is noted for high heat resistance. This is
                           Silicone                      a very soft thermoset insulation. It has excellent electrical properties plus ozone resistance, low
                                                         moisture absorption, weather resistance, and radiation resistance. It typically has low mechanical
                                                         strength and poor scuff resistance.
                                                         Signal to Noise Ratio. Commonly used interchangeably with ACR - the difference between
                                                         attenuation and crosstalk, measured in dB, at a given frequency (acronym for Attenuation Crosstalk
                             SNR                         Ratio). Important characteristic in networking transmission to assure that signal sent down a twisted
                                                         pair is stronger at the receiving end of the cable than are any interference signals imposed on that
                                                         same pair by crosstalk from other pairs.
                                                         The device (usually LED or laser) used to convert an electrical information-carrying signal into a
                            Source                       corresponding optical signal for transmission by an optical wave guide.
                           Spacing                       The distance between the centers of two adjacent conductors. Pitch.

                             STP                         Shielded Twisted Pair(s).

                            Strand                       A single uninsulated wire.

                    Stranded Conductor                   A conductor composed of groups of uninsulated wires.

                             Strip                       To remove insulation from a cable or wire. (6 of 7) [8/31/2001 9:54:17 AM]
Alpha Communications® GLOSSARY OF TERMS
                                                         Usually refers to affixing or mounting a station right onto the finished wall, without any of the internal
                     Surface Mount(ing)                  components (guts) protrude back into the wall.
                                                         A temporary and relatively large increase in the voltage or current in an electric circuit or cable. Also
                            Surge                        called transient.
                                                         Abbreviation for super VHS. A video format in which the two parts of the VHS video signal, the
                            SVHS                         chrominance and luminance, are transmitted separately providing for better picture resolution with
                                                         less noise.
                            Switch                       An electro-mechanical device which, when activated, makes and/or breaks an electrical connection.
                                                         DuPont Company trademark for fluorocarbon resins. (FEP - Fluorinated ethylene-propylene. A
                                                         thermo-plastic material with good electrical insulating properties and chemical and heat
                                                         resistance.). (TFE - Tetrafluoroethylene. A thermoplastic material with good electrical insulating
                          Teflon (R)                     properties and chemical and heat resistance.). It is not suitable where subjected to nuclear radiation
                                                         and does not have good high voltage characteristics. The cost of Teflon is approximately 8 to 10
                                                         times more per pound than PVC compounds.
                                                         The maximum temperature at which the insulating material may be used in continuous operation
                     Temperature Rating                  without change of its basic properties.
                       Tensile Strength                  The pull stress required to break a bare wire.

                       Thermal Rating                    The temperature range in which a material will perform its function without undue degradation.
                                                         Telecommunications Industry Association. Body which authored the TIA/EIA 568A "Commercial
                              TIA                        Building Telecommunications Wiring Standard" in conjunction with EIA.
                                                         An audible sound (tone) produced by the oscillating of a speaker, generated when an intercom
                         Tone Signal                     station wishes to signal another station by non-verbal means.
                         Transducer                      A device for converting mechanical energy to electrical energy.
                                                         An electrical device for transferring AC current from one voltage to another. Most intercom
                         Transformer                     applications operate at low voltage, and require a 'step down' transformer to reduce voltage to
                                                         system specifications (usually 16 or 24 volts).
                         Transmitter                     An electrical component used to convert an audible input to a variety of electrical signals.

                         Twisted Pair                    Two lengths of insulated conductors twisted together around themselves.

                             UHF                         Abbreviation for ultra high frequency, 300 to 3,000 MHz.
                                                         Abbreviation for Underwriters Laboratories, a nonprofit organization which tests and verifies
                              UL                         construction and performance of electronic parts and equipment, including wire and cable.
                                                         When a device has been submitted to and tested by UL and meets a specific UL Standard, it
                          UL Listed                      receives a UL Listing, indicating it meets that UL standard. There is no such thing as a device that
                                                         is 'UL Approved'.
                                                         A transmission line in which voltages on the two conductors are unequal with respect to ground. A
                      Unbalanced Line                    coaxial cable is a common type of unbalanced line.
                            USPS                         Unites States Postal Service.

                             UTP                         Unshielded Twisted Pairs(s).

                               V                         Volt.

                              VA                         Volt-ampere. A designation of power in terms of voltage and current.
                                                         Multi unit mailboxes with tall 'vertical' doors/compartments. Vertical mailboxes are the least
                     Vertical Mailbox(es)                expensive type of mail box, but tend to take up a lot of wall space (width). They are usually used in
                                                         smaller buildings.
                                                         Abbreviation for very high frequency, 30 to 300 HMz as designated by the Federal Communications
                             VHF                         Commission.
                             VHS                         Abbreviation for Video Home System. VHS is a trademark of Panasonic, Inc.

                            Video                        Pertaining to picture information in a television system.

                             VLF                         Abbreviation for very low frequency, 10 to 30 kHz.

                             Volt                        A unit of electromotive force.

                           Voltage                       Electrical potential of electromotive force expressed in volts.
                                                         The voltage developed across a component or conductor by the current flow through the resistance
                        Voltage Drop                     or impedance of the component or conductor.
                                                         The highest voltage that may be continuously applied to a cable construction in conformance with
                       Voltage Rating                    standards or specifications.
                              W                          Symbol for watt or wattage.

                             Watt                        A unit of electrical power.

                             Wire                        A conductor, either bare or insulated.
                                                         A multi-pin audio Connector (typically 3 pins) used in microphone, line level and snake cable
                             XLR                         connections.
                               Z                         Symbol for impedance (ohms).

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                                                                                                                                   Alpha Communications®
                                                                                                              42 Central Drive, Farmingdale, NY 11735-1202
                                                                                                                 Phone: (631) 777-5500 Fax: (631) 777-5599
                                                                                                                                 TOLL-FREE 1-800-666-4800 (7 of 7) [8/31/2001 9:54:17 AM]