If I install a video capture board in a computer and eventually want to add more cameras than that board has connectors, can I add another board?
Yes, in some cases. Multiple video capture boards are supported. Should you require additional cameras, another capture board may be added to the DVR adding additional camera ports. The upgradeability of the system depends on the initial configuration – please see the DVR cards pages for further information.

Why are color CCTV security cameras better than Black and White (B/W), even though B/W security cameras will work at lower light levels?
Traditionally, B/W security cameras were considerably less expensive than color security cameras, much more light sensitive and often of higher resolution. Today, the price gap has narrowed considerably, resolutions are basically the same, Now our Color camera are often 0.5Lux, it is often satisfactory with the day surveillance. If you really want to surveillance during night, our Infrared camera can work at 0 Lux with favorable price.

Why don't I need 30 frames per second video recording on all security cameras?
Video security systems are generally intended to allow the image capturing of intruders and crime perpetrators. The purpose of these systems is not to make movie quality videos. Recording rates of as low as 1 or 2 frames per second will catch virtually any criminal act. Some of our software compression DVR cards are economic and useful, such as REK-D104S, REK-D800S, REK-D416S. Of course, if your customers would pay more money and get the real time recording files, our hardware compression DVR cards have the best image. Please feel free to read our DVR cards specifications.

What does an auto-iris lens do for me?
Outdoor security cameras or cameras indoors facing a window or an outside door will have varying light conditions. CCTV display and recording systems are set to a certain level of image brightness and contrast. When light levels change in the images produced by the cameras, the displayed and recorded images will either be too bright and washed out or too dark and non-resolvable. The only way to solve this is to use an auto-iris lens. These lenses have an electric motor-driven iris which is opened or closed according to signals fed to it from the camera. Once set, a camera equipped with auto-iris drive will attempt to produce a video signal of constant brightness by opening or closing the auto-iris of the lens, as light levels change.

If I purchase fixed focal length lenses or security cameras with fixed lenses, can I exchange those if I don't like the field of view that I see?
Yes you can, provided they are shipped back in the original packaging and are in "as new" condition. However, you will be liable for the shipping charges, both ways and this, combined with the hassle involved, usually makes it an unsatisfactory thing to do. Better, in the first instance, if you are unsure about the lens focal length required, to purchase cameras with vari-focal lenses. These are manually adjustable over a range of focal lengths, most commonly from 3.5 to 10.5mm, to give a wide range of field of view.

How far from the DVR can I place security cameras?
Using RG59 Coaxial Cable, each CCTV security camera can be placed up to 600 feet from the computer and up to 1,000 feet with RG6 Coax. Even longer distances (>2,000’ )can be achieved using Baluns and CAT5 cable

Can I use my old security cameras mixed with new ones?
Yes, providing certain conditions are met. Even with the same color type, some older cameras and some newer cameras mixed together can cause problems because of very different image synchronizing systems. In this event, you can get interference between one camera image and another. Color cameras are more prone to this type of problem.

How many days/weeks of recording can I store?
This depends on how big is your hard drive, how many cameras are you using and under what conditions are you recording (on motion, on alarm, continuously, etc.) and what type of compression you are using. Assuming that you are recording only when motion is present (the most common recording method today) using a 30fps board and assuming that you have 4 CCTV security cameras and that there is movement in the surveilled area for 16 hours a day, 5 days a week, and you are recording at 320x240 pixel resolution with MPEG4 compression, you could expect to use up about 20 to 25GB of disk space per week. So, a 40GB drive would hold about 2 weeks of recordings under those conditions.
Of course, if you record at 640x480 pixel resolution, and/or you are using a 120fps or faster board, the disk space used will increase. Because of the way that MPEG4 compresses video, there is not a definite mathematical formula that can be applied to say exactly by how much the recordings would grow.
Since hard drives are now relatively inexpensive, it pays to use as big a capacity drive as possible (and/or multiple drives) if you are concerned with storing many weeks of recordings before overwriting.