The bench test 1: Flexible, affordable

The heart of the system is a VHS VCR with a built-in eight-channel camera switcher and system control functions. This is designed to work with a range of dedicated line-powered cameras, including discreet colour and black and white models and more substantial-looking designs in anti-vandal housings; all cameras have built-in microphones and either on-board or external PIRs.

The VCR, and its operating system, is controlled from hard-wired keypads or an infra-red remote control handset. It can also be used with one or two four-channel light switching units and, as with the keypads and handset receiver, they link to the VCR via a simple wired control bus that carries low voltage power and control signals.

We will begin with the VCR since this is the core component. Judging by the internal and external construction it seems to be largely based on a domestic VHS video recorder chassis with format standard SP and LP recording modes, both with mono sound.

From the front it looks fairly conventional but on the back panel, where the SCART AV and aerial connectors would usually be, there is a bank of mini DIN sockets for the cameras, two phono sockets carrying the video output for a monitor and audio, plus a multi-way socket, which carries the system bus and alarm connections.

The VCR has three basic operating modes: manual, continuous recording, and sensor-activated recording, the latter making the most efficient use of tape for unattended operation. There is also an 'In' mode, for monitoring cameras with recording disabled.

VCR functions are most easily controlled from the remote handset using a set of on-screen menus. Control from the keypads is possible, however they are likely to be in a fixed position, some distance from the monitor screen.

What's on the menu?
The first menu item is a log that records a range of system functions, including alarm activation and mode/status changes. Menu item two is a timer facility with 32 memory positions, each capable of instigating a range of actions including setting entry and exit times, switching lights on and off and enabling scan mode, set by start time and the day of the week.

Menu three is for the lighting controller. It has eight switched channels, which can be associated with each of the camera inputs; options include setting lighting levels and on times. Menu four gives access to three sub-menus. The first is used to set camera idents (number and eight-character title), on-screen display position, audio volume and switcher dwell and record release times.

The second sub-menu sets camera sequencing. Two 'lists' are available; the third sub-menu is concerned with a number of housekeeping functions including adjusting exit delay times, entry and exit camera selection, warning tones, recording speed (SP/LP) and light activation. Item five on the main menu sets time and date, and item six is used to set installer and user PIN codes.

External system control, in the form of keypads and the infrared handset, utilises the system bus. Keypads connect to the VCR via a simple four-way cable. The keypads are compact wall mounted modules with the illuminated buttons covered by a hinged flap. The unit has a set of camera selector, mode and alarm recording LEDs, plus a bleeper that confirms key entries and alarm activation.

The keypad is fitted with an anti-tamper switch, though this did not appear to do anything much on our sample. The remote control handset looks very similar to a regular VCR handset, though it has two numeric keypads, one for camera selection and the other for light switching functions.

Unfortunately the rather sketchy instruction leaflets did not make it clear that the handset doesn't communicate with the VCR directly. Instead it uses a small receiver module that has to be wired to the VCR's system bus.

The lighting controller is housed in an anonymous white metal box and once again it links to the VCR/switcher via the system bus. External units such as the lighting controller and keypads can be daisy-chained or wired directly to the multi-way socket on the back of the video recorder.

The controller unit requires its own independent mains supply and can handle up to four lights, each output rated at up to 550 watts. A jumper inside sets the communications address when two controllers are used together.

Cameras
Finally the cameras. We were provided with two types: the OPT780/780c, which is about the size of a tennis ball and has an on-board PIR detector; and the ATC82, which is available in B/W or colour variants (ours was B/W) housed in a vandal resistant housing with an external PIR.

OPT780 cameras are available in several different configurations including colour and black and white and with 3.6 or 4.3mm lenses, giving viewing angles of 90 and 72 degrees respectively. It is a fairly inconspicuous design, built inside a black or white case, with an eyeball-type mounting bracket.

Black and white models use a 1/3-inch CCD with a minimum sensitivity of 0.1-lux and a claimed resolution of 420 lines, while the colour models have 1/4-inch sensors with 4-lux sensitivity and 330 lines resolution. In both cases the PIR detector has a range of around 10 metres with a 90-degree viewing angle. Incidentally, the B/W cameras have built-in IR illuminators though curiously no mention of this fact is made on the installation sheet.

The cameras are supplied with 18m cables, terminated at one end with a mini DIN plug. At the other end there are bare wires, which go to a screw terminal inside the mounting bracket. This should not pose a problem but it caught us out, as until this point all wired connections had followed a fairly logical pattern of colour coding i.e. red to red, black to black and so on.

Expecting the same on the cameras was a mistake. White goes to yellow and yellow goes to blue. It took us a while to figure it out and we suspected a fault. To be fair, the wiring is clearly shown on the instruction leaflet and while there is no excuse not to 'RTFM' (read the flippin' manual – Ed), it would have helped if the manufacturer had stuck to a common wiring scheme.

The ATC82 camera looks quite impressive. It is in a serious-looking extruded alloy housing and the kit includes the external PIR, cables and mounting hardware. Closer inspection reveals a suspiciously small lens behind the front window and an internal examination confirms that the case is indeed mostly full of air, apart from a simple board camera module with integral lens.

It is mounted on a sliding chassis plate that also holds a screw terminal block, for the VCR cable (15m) and the connection to the PIR, which also comes with its own 15m cable.

The OPT780 and ATC82 cameras are effectively sealed units with no user or installer adjustments, so apart from wiring them up, and fitting the mounting brackets, there is very little to worry about. The single-sided instruction leaflet supplied with the ATC82 gives some basic advice about siting the PIR but apart from that, installers are left pretty much to their own devices.

VCR set-up is also fairly straightforward; the most time-consuming part is likely to be the timer configuration. Most of the other settings can be safely left on their defaults until camera and PIR positions have been fine-tuned and working and operating patterns have been established.

When the premises are occupied the system would normally be set to 'In' operating mode, with all cameras active and recording off. Cameras can be set to auto sequence or switch, according to inputs from the PIR sensors.

Pressing the 'Out' switch activates a brief exit delay, after which time the cameras go into sequence mode. If a PIR senses activity, recording from the associated camera starts automatically, for a preset period or until the trigger has stopped.

At the same time the event is logged.

To view a recording, playback on the VCR can be controlled from the IR handset or a keypad. It operates in a more or less identical manner to a domestic VCR, with picture search and still frame replay modes. When the tape reaches the end, it is automatically rewound and the system returns to its previous state.

Recordings are not indexed or protected in any way so it is possible for potentially important material to be over-recorded.

Performance
VCR performance is in line with domestic models and in SP mode, on good quality tape, resolution is fairly close to the stated 240 lines. Noise levels are average but colour rendition is good. Resolution takes a dive in the LP recording mode and there is a noticeable increase in noise and a drop in picture stability.

Image quality is influenced by a number of other factors, including the cameras and the internal switcher. Camera inputs are unsynchronised and the image jumps at the switchover point, which can be quite annoying when pictures are being monitored.

This also affects recordings and the momentary lack of synchronisation can cause the recorded picture to lose stability for several seconds.

Camera performance is variable; the best results were obtained form the black and white version of the OPT780. The image was crisp with a wide dynamic range and very little noise. The ATC82, on the other hand, produced a slightly softer, less detailed image.

Both cameras responded quickly to changes in lighting levels, however the OPT780 worked better at low light levels, with less noise in the image, and the built-in IR LEDs are bright enough to illuminate objects within a metre or two of the lens in total darkness.

As expected, the colour version of the OPT780 produced a slightly less detailed image compared with the B/W model. The automatic exposure controls were also less agile and our sample had difficulty coping with brightly illuminated scenes, or spot lighting within the image area.

Audio recording in all cases was satisfactory, not exactly hi-fi quality, and there is a fair amount of background noise. But the microphones are quite sensitive and able to pick up conversations two or three metres away when background noise levels are low.