CLOSED CIRCUIT TELEVISION
A Closed Circuit Television system is a multipurpose tool. Closed Circuit Television (or CCTV) when properly designed and installed is a most effective tool for purposes of:
*Visual verification of events in the business and home.
*A management tool for business (especially when combined with a video recorder)
*A convenience and labor saving tool for business
A convenience tool for the home
*An advertising tool when used "live" on a Web Page.
A CCTV System:
CCTV Camera and a CCTV Monitor
Enhancements to the CCTV system can include:
*
Additional cameras, video recorder, switcher, and/or quad Splitter
*Pan /Tilt/ and Zoom controls can be added to the camera(s)
*
Video transmission over phone lines can make viewing possible from anywhere in the world.
Recorders:
Video Time Lapse Recorder
( records up to 960 hours on one VHS tape)
Digital Video Recorders
"The first True VCR Replacement"
The newest improvement to CCTV system design is the DIGITAL RECORDERS. With these units, the need for VHS tapes is eliminated. The video images (up to 60 pictures-per-second) are stored on a computer hard-drive. Navigation controls are easier than those on a simple VCR.
Among the most notable improvements!:
No more need for VHS tapes.
*Improved clarity of recorded picture
*Record current view while viewing old recording simultaneously.
*Improved dependability.
Most digital recorders come with hardware and software necessary for remote viewing of live and recorded pictures on your home computer. 
16 camera inputs with built in multiplexer
PASSIVE VS INTERACTIVE
CCTV Systems
A Passive design is made when the cameras are installed at a location with a fixed lens. A recorder is turned on, and that view is captured on the recorder. No operator is necessary, and if the cameras are placed in correct positions and the correct lenses have been chosen, then a proper visual record will be archived.
An Interactive design is made when the camera is installed at a location with a pan and tilt motor and possibly a zoom lens or cameras are combined using a sequential switcher. A full time operator is constantly working with the controls to view many areas............ The recorder is recording what the operator is seeing. This is an important weakness in the interactive system. If the operator pan, tilts and zooms onto a suspect at the jewelry counter (for example) the operator is not seeing, and the recorder is not recording the employee 20 feet away (as another example) stealing money out of the cash register.
Generally speaking a Passive System is best. If interactive components are added, the system's integrity must be maintained by having enough passive cameras viewing and recording the areas of most critical concern.
LENS SELECTION
Here are two views of the beach from the same camera position. 
TheTop Left picture shows a small part of beach and a close up of the tourists.
The BottomRight side picture shows more activity on the beach, but with less detail of individuals.
Think in terms of having a detail camera or a wide angle scene camera. 
You CANNOT have a wide angle lens that will view the whole room and still give you the close up detail to view the denomination of money tendered, or a good face view of the customer. More than likely, your CCTV system will need a combination of scene -type wide angle lenses and detail -type narrow lenses.
Switchers, Quad Splitters and Multiplexers
When there is more than one camera to be archived on a single recorder or to be viewed on a single monitor then some type of combining device is necessary. The least expensive is the automatic sequential switcher . This device will switch from camera to camera automatically, and will allow recording of each camera (one at a time) on a single recorder. Better, is the quad splitter . This more expensive box will show four cameras on the monitor at the same time, and these four images are recorded in this same format. The only draw back here is that these are four small pictures. Best is the multiplexer . This device will show up to 16 cameras on one monitor at the same time. However, EACH picture is recorded singly, so that on the play-back of the recorded images, you can view any one camera you want "Full sized". Most multiplexers today have built in motion detectors so that only the cameras that are viewing motion are sending a signal to the recorder.
SAMPLE OF QUAD SPLITTER
Storage Area (rear exit to left)
Drive Thru Window+Register
Main Registers
Dining Room (Camera over Exit)
CCTV has a most convenient application for the home. A single camera can be installed at the front door, or (for example) several cameras can be installed to view: the front door, the entrance gate, the swimming pool and the baby's room.
For the sake of security , these views can be recorded on a time lapse recorder that archives up to
960 hours on one tape. For the sake of convenience , these camera views can be programmed onto your television's cable or antenna signal.
A "modulator" will let you program the CCTV; pictures to be viewed on an otherwise unused channel.
Below is a picture, captured from a TV set, that is viewing the front entrance of a home using their selected channel # 78.
Below is a sample of a Picture-In-A-Picture Splitter. Included with the CCTV design at this location is a Cash Register Text Inserter. This is an excellent example of how much information an owner/manager can review by using the recording from a simple CCTV design.
The store front is viewed so that management can "See" all visitors and what product has been served to the customers. The text inserter lets management see how much was tendered on the cash register for the product sold to customer. The smaller picture shows the back storeroom, and is positioned above the rear exit so that management can view product being delivered or remove from this exit.
