Recording is essential to the effectiveness of any video security system. Without recording, you need to have an employee watching a monitor at all times - hardly a cost-effective solution. And even if you spot suspicious activity, without a recording, you have nothing to use in court.

Almost all video security systems include some sort of recorder to store the images the cameras capture. Only a few years ago, the universal solution was the familiar VCR. However, the introduction of digital video recorders (DVRs), which record onto hard drives instead of tape, has dramatically changed the situation.

DVRs offer so many advantages over VCRs that they have rapidly taken over as the CCTV recording solution of choice:

• Ease of locating events- Instead of fast-forwarding through hours of tape, DVRs can instantly retrieve images from any specific time or date, or automatically skip to the point on a recording when something changed.
• Storage quality- Like all tapes, video cassettes start deteriorating almost immediately once you record on them - and the problem gets worse every time you reuse them. DVR recordings have no degradation at all since they are stored onto a hard drive.

• Multitasking- While analog VCRs can either record or play, most DVRs can do both at the same time, letting you review images while still recording.
• Smart monitoring- The DVR can be set to take one picture per second or less - just enough to create a running record. However when it detects motion, it can automatically bump the recording speed up to full (30 frames per second), getting every detail of the unauthorized activity.

For businesses that do not want to constantly change tapes, DVRs are definitely the way to go. While security VCRs usually offer a time-lapse mode that lets them for long periods of time, the resulting images are not a good record of events - they record only one snapshot every eight seconds. To get higher quality, you need to change tapes every day or more often. DVRs, on the other hand, can record for weeks or even months.

DVRs are more considerably more expensive than VCRs, which is their only major drawback. However, the DVR prices have fallen considerably over the last year and will continue to do so. Already, low-end DVRs and high-end VCRs are in similar price ranges, and most manufacturers have stopped introducing new VCR models. Despite the increased cost, we recommend video security system buyers purchase a DVR whenever possible.

Choosing a DVR
As part of your CCTV shopping preparations, decide how much quality you need out of your recorder. There is no magic number or spec here: you need to decide how "good" the recorded picture needs to be, either for your own use later or possibly to use in court. Once you decide this, you will be able to look at samples on the DVRs you are evaluating and see if they meet your standard. Vendors may be eager to throw compression settings, pixel counts, and other statistics at you - but those numbers are irrelevant if the picture itself does not offer the detail you need for legal or investigatory purposes.

The size of the hard drive will dictate how much you can record. On the low end, an 80-gigabyte (GB) hard drive will store about five to eight days of full-motion video from one camera. Most of the time you will not be recording full motion, so this is much more than it might seem. For most businesses, spending a little extra to get 120 or 240 GB is a worthwhile investment. Units expand up to 1.2 terabytes (1,200 GB), which can store many cameras' worth of data for long periods of time.

Replaceable hard drives are a cheap way to boost storage capacity. With some DVRs, you can buy additional hard drives for as little as $150 and swap them in and out as you need. This gives you the advantage of being able to store your data separately from the main security system.

You will also need to consider how many cameras you want to connect to the DVR. Keep your future expansion needs in mind - buying a higher-grade model to get more inputs and more storage space can save you considerable money in the future. The DVR will also function as a multiplexer, putting up to 16 cameras on one display and allowing operators to call up any one image for closer inspection.

Also, if you ever have to use your security images - in court or in other ways - you will need to be able to export the video. This is an important consideration: some systems let you create industry-standard .avi files, which can be played on any PC, and burn them to CD. Others only allow you to export proprietary formats that can only played on the same brand player. Most DVRs do offer the option to connect a standard VCR - this allows you to simply tape the digital recording onto a standard VHS cassette.

Choosing a VCR
If you decide to save money by going with a VCR, make sure you purchase a model built for video security system usage, not a consumer VCR. Purpose-built security VCRs offer far more reliable operation than home models, so they can stand up to constant operation.

The main feature to look for in a VCR is how many hours it can record: models range up to 960 hours on a standard tape. Remember, though, that these extended recording times result in fewer frames per second.

Be aware of the hidden and ongoing costs of VCRs. Buying, rotating, and replacing VCR tapes can be expensive and time consuming. Constant usage creates quite a bit of tape debris inside the machine, requiring expensive regular maintenance. And in addition, if you have multiple cameras, you will need a multiplexer - a separate piece of hardware that combines multiple video images into one - to avoid purchasing a separate VCR for each camera.