A licence may be required to operate

A licence may be required to operate a microwave frequency system. It has an outer diameter of around 6 mm and it is a good compromise between maximum distances achievable (up to 300 m for monochrome signal, and 250 m for colour) and good transmission.ND FILTERSNeutral Density filters are optical filters that attenuate the light a number of times.REMOTE CONTROLA transmission and receiving of signals for controlling remote devices such as pan and tilt units, lens functions, wash and wipe control and similar.PHOTO-EFFECTAlso known as photoelectric effect.QUAD COMPRESSOR(Also split screen unit). The RS-232 standard defines a scheme for asynchronous communications, but it does not define how the data should be represented by the bits, ie. Objective.RG-11A video coaxial cable with 75 Ohms impedance and much thicker diameter than the popular RG-59 (of approximately 12 mm). Indicates the magnification of the image when compared to an image from a standard angle lens.POTSPlain Old Telephone Service, ie.PALStands for Phase Alternating Line, which describes the colour phase change in a PAL colour signal.PAN AND TILT HEAD(P/T head).MANUAL IRISType of lens that requires manual focusing. For a sine wave signal such as the mains, the RMS value happens to be 1. A must for any CCTV technician. It is usually used to describe alarms in CCTV. 

Very similar to RG-59, only slightly thinner.RANDOM INTERLACEA term describing a camera that has a free running horizontal sync as opposed to a 2:1 interlace type which has the sync locked and therefore has both fields in a frame interlocked together accurately. it does not define the overall message format and protocol. This attenuation is equal for all the wavelengths therefore it does not change the colour balance of an image, hence the term neutral. It is expressed as the square root of the difference of the squares of the indices of the core and the cladding. A measure of the angular acceptance of light incoming into a fibre optics cable, in the form of a cone. The RS-422 can drive lines of over a kilometre in length and distribute data to up to 10 receivers. The principle point closer to the imaging device (CCD chip in our case) is used as a reference point when measuring the focal length of a lens.RS-485This is an advanced format of digital communications compared to RS-422.RAMRandom Access Memory.RG-59A type of coaxial cable that is most common in use in small to medium size CCTV systems.ROMRead Only Memory. A modem is used to convert between analogue and digital signal to then transmit and receive the signals over the PSTN network. In photography, polarising filters are used very often to darken a blue sky. Some older video test charts carry the name "RETMA Chart".PINHOLE LENSA fixed focal length lens, for viewing through a very small aperture, used in discrete surveillance situations.RAIDRedundant Arrays of Independent Disks. Often used in CCTV to describe a device that is primarily used to multiplex several video signals into one for the purposes of recording or microwave transmission.PLUMBICONThermionic vacuum tube developed by Philips, using a lead oxide photoconductive layer.NBSNational Bureau of Standards (USA). Its capacity is measured in kilobytes.RETMAFormer name of the EIA association. In simple terms, the signal transmitted is "read" at the receiving end as the difference between the two wires without common earth.NTSCNational Television System Committee, an American committee that set the standards for colour television as used today in USA, Canada, Japan and a few other countries.NOISEAn unwanted signal produced by all electrical circuits working above the absolute zero.N/C AND N/O ALARMSRefers to Normally Closed and Normally Opened contacts.MULTIPLEXERA device that combines a number of signals into one.41 times (square root of 2) below the peak values.PRINCIPLE POINTAn optical term that refers to one of the two points that each lens has along the optical axis.MICROWAVE TRANSMISSIONA method of transmitting signals using a microwave frequency link.OSCILLOSCOPE(Also CRO, from "Cathode Ray Oscilloscope").O/POutput. An electronic device, usually a part of a video matrix switcher, which receives digital, encoded control signals in order to operate pan, tilt, zoom and focus functions. It represented the ultimate imaging device up to the introduction of CCD chips. Usually 24 VAC motors are used in such P/T heads, but also 110 VAC, ie.OCULARThe very last optical element at the back of a lens (the one closer to the CCD chip). The major improvement is in the number of receivers that can be driven with this format, and this is up to 32. One phot is equal to 10,000 luxes. A motorised unit permitting vertical and horizontal positioning of a camera and lens combination. Generally used in larger and more complex systems the matrix will usually also incorporate a range of additional advanced features. An electronic chip, containing digital information that does not disappear when power is turned off.PHOTA photometric light unit for very strong illumination levels. Usually refers to the CCD chip unit picture cell.MODEMDerived from the term Modulate-Demodulate. The lens normally has no focusing control but offers a choice of iris functions.PTZ SITE DRIVER(PTZ site receiver, or decoder). 

Also known as PSTN. It consists of a photo sensor plus its associated control gates. the telephone service in common use throughout the world today.MULTIPLEX VIDEO RECORDINGThe condensed recording of more than one video signal on a single videotape, or hard disk drive. A representative of the quantum nature of light. Photon. All AC voltages are measured with multimeters that show the RMS value of the signal (not the peaks). An electronic device that can measure the signal changes versus time. Noise cannot be eliminated but only minimised.PSTNPublic Switched Telephone Network usually refers to the "plain old telephone" service.PIXELDerived from picture element. The effect is such that it can eliminate some unwanted bright areas or reflections, such as when looking through a glass window. It is also known as a serial data communication..MATRIX SWITCHERAdvanced type of switcher in which a signal from any input can be switched to any number or combination of outputs. It usually China Custom Flexible Jaw Couplings Suppliers refers to four quadrants display.RG-58A coaxial cable designed with 50 Ohms impedance, therefore not suitable for CCTV.

 This refers to a phenomenon of ejection of electrons from a metal whose surface is exposed to light.PRESET POSITIONINGA function of a pan and tilt unit, including the zoom lens, where a number of certain viewing positions can be stored in the systems' memory (usually this is in the PTZ site driver) and recalled when required, either upon an alarm trigger, programmed or manual recall.RS-422This is an advanced format of digital communication when compared to RS-232. Not affected by adverse weather but requires direct line of site. With RG-11 much longer distances can be achieved (at least twice the RG-59), but it is more expensive and harder to work with.PHOTOPIC VISIONThe range of light intensities, from 105 lux down to nearly 10-2 lux, detectable by the human eye. One nit is equal to one candela per square metre of a projected surface area.RMSAn abbreviation for Root Mean Square.RS-232A format of digital communication where only two wires are required.NANumerical Aperture.MAGNIFICATION RATIOThe ratio between the focal length of a lens and the focal length of a standard angle lens.RF SIGNALRadio frequency signal that belongs to the region up to 300GHz. The basic difference is in the need for four wires instead of two as the communications is not single-ended as with RS-232, but differential. Equipment which simultaneously displays parts or more than one image on a single monitor.MULTIPLEXThe concept of transmitting several signals on a single channel.PHOTODIODEA type of semiconductor device in which a PN junction diode acts as a photo sensor. It is considered as the smallest unit of light