CCTV Camera/ Device Installer

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“CCTV Camera/ Device Installer related Frequently Asked Questions by expert members with professional career as CCTV Camera/ Device Installer. These list of interview questions and answers will help you strengthen your technical skills, prepare for the new job interview and quickly revise your concepts”



45 CCTV Camera/ Device Installer Questions And Answers

1⟩ Tell me should I use IP system?

IP cameras require a network only for them. Otherwise they gonna reduce the system’s performance. Also, it is a more complicated technology to deal with. It requires a little bit of knowledge in Network Systems in order to make it work well.

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2⟩ What is CCD Charge Coupled Device?

Charge Coupled Device, CCD, is one of the two main types of image sensors used in security cameras. When a video is recorded, the CCD is struck by light coming through the camera's lens. Each of the thousands or millions of tiny pixels that make up the CCD converts this light into electrons. The number of electrons, usually described as the pixel's accumulated charge, is measured, and then converted to a digital value. This last step occurs outside the CCD, in a camera component called an analog-to-digital converter.

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3⟩ What is Infrared (IR)?

Low frequency light below the visible spectrum. Infrared is used in surveillance cameras to provide a light source to record images in dark and zero light conditions.

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4⟩ What is MPEG?

The Motion Picture Experts Group (MPEG) released MPEG-4 encoding in 1998. The basic idea behind MPEG is that compressed images are compared before being transmitted over the network. The first compressed image is used as a reference and compared to the images that follow it in the video sequence. The first image is transmitted over the network along with the parts of the following images that differ from the initial reference image. The viewing application on the receiving end of the transmission then reconstructs all images based on this information and displays the result. This is a simplified description of how MPEG-4 works.

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5⟩ Tell me what is pixel?

A pixel refers to an individual area on the surface of the imaging device, normally a CCD. It is made from photosensitive material which converts light into electrical energy. In the context of a display monitor, a pixel is also referred to as an individual area on the surface of the screen which converts electrical energy to visible light.

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6⟩ What is WDR Security Cameras?

A WDR security camera (Wide Dynamic Range) is used for capturing clear images of objects surrounded by a strong back light, while still keeping the background visible.

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8⟩ What is balun?

A Video Balun enables the transmission of video using unshielded twisted pair wire instead of coaxial cable. The word "balun" comes from combining the terms balanced and unbalanced. The function of a balun is to transform an unbalanced signal into a balanced signal. When video signal is transmitted through coaxial cable, the distance traveled by the signal is limited because the signal is in the form of an unbalanced signal that is susceptible to Radio Frequency Interference or noise. Coax cable incorporates special shielding to minimize noise. Video Baluns transform the video signal into a balanced form in which each wire in the twisted pair transmits an identical signal with opposite polarized magnetic fields. Noise affects each signal equally. When the signals are combined, the noise is cancelled out. By using a designed balun, an unshielded twisted pair wire can transmit video for much longer distances than coax cable and with a lower cable cost.

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10⟩ What is multiplexer?

This is a device that takes inputs from 2 or more video channels and combines them into one signal. This is often done by using time division multiplexing, which interleaves frames from each channel in such a way that they can be split out again. Frequency division multiplexing uses different frequencies to achieve the separation of the signals.

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11⟩ What is RS-232?

RS-232 is a communications standard for serial communications between devices. In CCTV, this can be communication between a contoller and a surveillance camera. The RS-232 standard allows for the connection of two devices through a serial link, and is the protocal used for serial connections in computers. RS-485 allows for serial connections between more than 2 devices on a networked system and is defined below.

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12⟩ What is Varifocal (Zoom)?

This refers to a type of lens that has the capability to change the focal length. This allows adjustment of the magnification and field of view of the security camera.

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13⟩ Tell me what App do I have to use for the DVR’s?

Analog DVR’s: I watch DVR

AHD DVR’s: I watch DVR

SDI DVR’s: I watch DVR

IP NVRS: I watch NVR

TVI DVR’s: For Karbontech: Super Live Pro or I watch DVR (Depending on the DVR model). For Hikvision: IVMS 4500

CVI DVR’s: Dahua DVR – IDMSS (Apple Cellphones) and GDMSS (Android Cellphones).

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18⟩ What is Iris?

The mechanical device that adjusts to vary the amount of light passing through the lens of a camera.

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20⟩ What is Impedance?

The total opposition offered by a device to the flow of an alternating current. Measured in Ohms.

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