CCTV Systems
By John W. Colley

Grill The CCTV Expert
March, 2003 Issue

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Why has digital video replaced analog video?

Simply digital video has better consistent quality, price and reliability. Digital video offers raw pixel counts that allow files to grow. Compression of digital has many options. The refresh rate is selectable. In addition, digital video provides images to be stored indefinitely, transmission is immune to noise and can be copied exactly.

One of our clients asked, "Why are most CCTV systems manufactures using digital control and management of video systems?"

Digital allows you to select video to transmit or store the information. The ease of search on time, motion, event, calendar dates is a large advantage. Using standard options of zoom, focus, fast-forward, reverse coherently improves control functions. Digital management removes human intervention, utilizes auto-archiving, and allows for remote and local storage. To change field rate will be digitally and will not be dependent on hardware.

A bank client recently requested that we mix video with their ATM machine. What are some standard features we should ask our CCTV/Interface manufactures to supply?

First you should ask the ATM Interface manufacture who have they done similar ATM systems with and to provide people to talk to at the customer locations. Standard features should include: programmable alarm outputs, an auto network configuration tool using SDLC or Bisync, battery backup of the electronics, time and date generator synced to the host computer, exceptions to a standard configuration should be designed to allow for flexibility, time and date stamp on exception data output. Programmable outputs that can automatically trigger by text to control CCTV devices i.e. PTZ, Access Control, VCR, digital recorders, etc.

What is an electronic shutter associated with CCD cameras?

Older CCD cameras used the video output level of a camera to adjust and control an auto-iris lens. Thus, an electronic shutter was required. The earlier versions of CCD cameras were always running at full power. The new versions of CCD provide the internal circuitry to control the shuttering of incoming light. The internal circuitry controls more light, less light and allows the use of non auto-iris lens. The change in the lens drops the total cost of the camera ensemble.

Our client wants to upgrade his black and white CCTV system to a color CCTV system. What do we need to consider when we quote this color camera upgrade?

Key components include external and internal lighting, choice of camera sensitivity, powering of cameras, providing new lenses not just new color cameras. A color camera will use 1X to 2X the amount of light than a black and white camera uses. Your choice of new lenses should allow for color corrections. Inspection of the existing power whether it is 12vdc, 24vdc or 115vac and providing a matching system components or allow enough installation dollars to install the proper power supply. Coaxial cables should be of the highest quality. The loss of video level will affect a color system more than a black and white system.

What are standard coaxial cable distances for CCTV camera installations?

Standard distances by type of coaxial cable used are as follows: 750 to 1000 feet for RG-59U, 1200 to 1500 feet for RGU-6 and 1800 to 2000 feet for RG-11. Best installation results are attained using a copper center and is highly recommended.

What are the installation guidelines that should be followed when bending coaxial cable around a corner in a CCTV installation?

The recommendation is a 60-90 degree bend within a distance of 2 to 6 inches. Exceeding this angle will cause a separation of shielding which causes noise and possible high frequency signal attenuation.

What type of features should we consider when evaluating driver license identifications systems?

Many restaurants, liquor stores and other retail applications are using video to record driver licenses and time stamping to protect the business from underage youths or verification of customers for cash checking activities to name a few applications. Features to consider include: the identification interface device should work with most CCTV cameras, record times can be adjusted, interface too most recording devices, should be small and compact, provide for a video input and video output.

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John W. Colley is president of Integrated Security Systems, Ltd. and has been in the security industry for over 25 years, beginning his experience in the CCTV segment of security and gaining knowledge through field experience, manufacturer training and designing systems to meet customer needs. Colley started his security integration firm 18 years ago, providing design, engineering, installation and service to commercial accounts using integrated systems. Send your CCTV/Surveillance questions to jwc@securityiss.com.