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PHILIPS VSS8250 PRO-VISION SYSTEM
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Philips Pro-Vision is a compact, modular
multi-camera surveillance system, designed for small to medium-scale installations.
The core component is the VSS8250 14-inch colour monitor/switcher unit, with
provision for up to four VCM 9175 line-powered colour cameras. Additional
cameras can be connected, using one or two external junction boxes, which
increases the system’s capacity to 7 and 10 cameras respectively.
The key features are ease of installation, flexible
operation and expandability. Cameras connect to the monitor/switcher using
pre-formed cables (4-wire twisted pair) with US-style RJ 11E telephone plugs at
either end. Cable runs of up 150 metres are possible, these can be extended by
up to 200 metres at a time, using an optional adapter box. The cable carries
the video signal, camera power, plus two-way audio (with an optional intercom
box) and switching signals for external devices.
MONITOR SWITCHER
The monitor/switcher unit is housed in a
sturdy white-fronted, metal-framed cabinet with a retractable tilt-stand on the
base. All of the switcher’s functions are controlled from a multi-lingual
(English, French or Dutch), menu-driven on-screen display. The main menu covers
pre-setting the camera switching order, sequence time (fixed intervals of 2, 4,
7, 10, 20 and 60 seconds), alarm configuration, time/date overlay, language
selection and VCR record/replay options. These include a multiplex mode,
whereby the camera switching rate is increased to 25 frames per second (the
monitor display is disabled). Multiplex recordings can be replayed a frame at a
time on VCRs (with stable still-frame replay), or via a de-multiplexer.
Front panel controls comprise a master
on/standby switch, buttons for menu call and select, camera up/down selection,
sequence start/pause, ‘talk’ and ‘action (more about those in a moment. The
menu buttons can be disabled, to prevent tampering or restrict operation; a
4-digit user-defined PIN code is required to unlock the controls. Behind a
hinged flap that runs the width of the front panel there are adjustments for
volume, colour saturation, brightness, contrast and a recessed pre-set for
horizontal shift. In the monitor standby mode the display is disabled but the switcher
and cameras remain active, so the output may be recorded, or viewed on external
monitors.
In addition to the four dedicated camera
inputs on the back panel it has a set of video and audio input/outputs (phono/RCA
sockets) for a VCR loop-through, plus secondary video and audio outputs, for a slave
monitor. There’s also a screw-terminal block for the alarm output connections.
Incidentally the PIN-coded control lock is
only moderately secure, as we discovered when the mains plug worked loose, momentarily
disrupting the supply, erasing the stored code. The PIN can also be reset -- if
it’s lost or forgotten -- using a simple procedure outlined in the instruction
manual.
ALARM OPTIONS
Various alarm configurations are possible. In
the absence of any additional sensors an alarm bleeper will sound, an on-screen
display appears and the switched alarm output on the back of the monitor is enabled
when there’s a break or short circuit on any of the camera inputs. Optional alarm
boxes with N/O or N/C contacts can be connected to any camera. When triggered by
a sensor (door/window contact, PIR etc.) the switcher stops sequencing, displays
the relevant camera output, along with an on-screen display and the alarm
bleeper sounds. The switcher can be programmed to reset and return to normal
operation after a pre-set delay of 30 seconds or 3 minutes, or it can be set to
remain in the alarm condition until manually reset. The time and date of the last
alarm event (but not the camera ident) is logged and displayed on the camera
select menu.
The cameras are fitted with built-in
microphones, with the audio heard through the monitor speaker. The optional
intercom box connects between the camera and the end of the monitor cable; a
microphone is mounted behind the front panel, next to the ‘talk’ button;
pressing it allows the user to be heard over the intercom speaker. The monitor’s
‘action’ button is used to activate a relay inside an optional action-box, that
also connects between the camera and monitor cable. This can be used to operate
external devices, such as a remote door lock. Although the system has been
designed to use the VCM9175 and compatible colour or monochrome cameras, other
makes and types can be connected with a camera interface box. This has sockets
for composite video and RF inputs.
CAMERAS
The VCM9175 colour camera is housed in a
small (60 x 7`2 x 92 mm) shielded plastic case. The image sensor is a 1/3-inch
CCD with 300k active pixels. The operating range is quoted as 3.5 to 30,000 lux,
with a resolution of 330-lines. The front of the camera is fitted with a CS
mount and it comes with a 4 mm F1.2 lens as standard. Other types of lens can
be fitted; there’s an auto-iris socket on the back, next to the ‘telephone’ socket
carrying the power and video feeds. The only user adjustment is a miniature slide
switch for turning the built-in microphone on or off.
Mounting hardware is supplied in the shape of
a universal wall bracket with a ball and socket head, that screws into a
threaded collar (1/4-inch UNC) on the underside of the camera. This is
different to the illustration in the instruction manuals, which shows the
mounting collar on the camera’s back panel, a small bolt-on right-angle plate
is included so that it’s possible to use an overhead or ceiling type mount with
the supplied bracket.
Both the monitor/switcher package and cameras
come with reasonably comprehensive installation instructions, including useful
advice on camera positioning and lens selection, for specialist applications. An
optional weatherproof housing is available for outdoor installations or harsh
environments.
INSTALLATION
It’s difficult to imagine how Philips could
have made it any simpler with only one connecting cable per camera to worry
about. Even the mounting bracket comes complete with screws and wall-fixing
plugs, in fact the only tool needed to install the system is a screwdriver...
Programming the sequencer and alarm functions is fairly painless, the only
other set-up adjustments concern the use of cable extension, alarm and junction
boxes (if fitted), aligning the cameras and focusing the lens.
PERFORMANCE
The supplied cameras performed well with
resolution spot on the stated 330-lines. The auto exposure system is responsive
and capable of dealing with sudden changes in lighting level. In the sequence
mode the image sometimes pulsates for a few moments if the scene contains a
single bright light or reflected sunlight. On a short duration sequence (2-4
seconds) the camera may not compensate in time before the image switches. so
care needs to be taken during camera alignment to prevent this happening. Low
light performance is good, yielding a useable, though somewhat grainy image, down
to typical room lighting conditions.
Colour accuracy is also very good in strong
natural and mixed lighting conditions. Reds and greens appear slightly exaggerated
in tungsten light whilst tube lighting results in a slight greenish-yellow
caste.
The switching action is very smooth, it
occurs within a single frame with no visible picture disturbance at the
changeover points. In the event of a power interruption the system switches
back on to the previously selected mode, the clock has a long-term battery
backup and will not require re-setting.
OVERALL ASSESSMENT
There’s a few minor niggles. The most
annoying one occurs when the system is in multiplex recording mode, where the
time/date overlay is suppressed. This means that unless the VCR has a time/date
stamp there’s no easy way of logging non-alarmed events, especially on
long-duration recordings. It’s a good idea to switch the monitor off when the
system is in this mode as the display becomes slightly unstable. The alteration
to the mounting collar layout on the cameras is a nuisance, and the alarm event
log is fairly rudimentary.
Apart from that the system works very well
indeed, and it’s worth repeating that it’s virtually idiot-proof, exceptionally
simple to install and use, once it has been set up. Image quality is good and
the cameras can cope with a wide range of undemanding lighting conditions
without difficulty. Philips have struck a realistic compromise between performance
and features. The system should easily meet the needs of most end-users,
looking for a simple and cost-effective multi-camera system, that easy to
install, operate and maintain.
PRODUCT ASSESSMENT
Design and design features ****
Circuitry and components ****
Ease of installation and wiring *****
Range and variety of functions ****
Accompanying instructions ***
Technical advice and backup ****
Value for money ****
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Ó R.Maybury 1995 0609
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