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DEDICATED MICROS 4 PLEX-QK
One of the more significant contributions digital video signal
processing has brought to the surveillance market is low-cost image
multiplexing; it's a highly significant technology that until recently was
uneconomic for small-scale commercial, industrial or domestic installations.
The Dedicated Micros' 4Plex-QK is a good example of how the technology has been
cut down to size.
It's a sophisticated, yet easy to use multi-channel video
multiplexer that can take the inputs from up to four standard colour or black
and white cameras, and process them, so they can be recorded by any VCR as
sequenced full-screen images, along with camera idents, time, date and alarm
tags. Recordings replayed through the unit can be viewed either full-screen or
in quad/split screen displays. Numerous alarm options are available, and most
operating parameters can be tailored to suit individual installations, via a
comprehensive menu-driven on-screen display.
Externally there's not much to see, it's housed inside a slim,
black metal box measuring just 210 x 45 x 335 mm. The front panel is occupied
by seven recessed push-buttons, each with its own red LED indicator. An eighth
LED, in the bottom right hand corner of the panel, acts as a power-on
indicator. The back panel is almost as sparse. From left to right there's an
8-pin mini DIN socket for DC power input, 7 BNC sockets for the various
composite video inputs and outputs, and one 9-pin D-connector which handles all
of the alarm inputs and outputs. Four of the BNC sockets are assigned to the
video inputs, one is for the monitor output, and the two remaining ones handle
VCR video input and output.
Power is supplied by a universal switch-mode mains adaptor that
operates from a 100-240 Volt AC 50/60Hz supply. Although compliant with several
recognised safety standards it nonetheless runs quite hot and installers would
be well advised to locate it in a well-ventilated position. Inside the casing
there's a single, densely-populated PCB with a high proportion of
surface-mounted components. It has been very well built, and apart from
component failure there appears to be little that can go wrong. Battery backup
for the clock, set-up and mode settings is provided, in the event of a power
failure.
Most of the front panel buttons have dual functions. Starting from
the left, the first four buttons are the camera input selectors, they also act
as set and change keys for the on-screen display, when the unit is in the
set-up or time/date adjust mode. Button number five is used to select the
replay mode, next to that is the recording mode selector, the final button
starts and stops automatic sequencing.
Pressing the quad and record buttons together brings up the main
set-up menu. Initially the first page covers language selection (English,
French, German, Spanish and Italian), after that comes the main menu with the
first option highlighted. This happens to be VCR selection, with over 20
popular time-lapse and surveillance machines included. It also has a VCR patch
table, for any models that are not listed. This allows the operator to key in
the delay values for the machine they're using. Options are also included for
non-time lapse machines
The remaining menu selections include setting the number and type
of camera inputs, creating 5-character camera idents, setting the camera dwell
time (1-999 seconds), setting the alarm inputs (normally open, normally closed
or no input) , selecting the many and various alarm options, resetting the
system back to factory defaults and setting up an operating schedule or event
timer. For some reason no explanation for this facility was given in the
otherwise comprehensive instruction booklet supplied with the unit. That's
slightly ironic in view of item on page 1 of the documentation which proclaims
' 4Plex-QK is a product requiring minimum set up and operation skills. Only
this manual -- Owners Operating and Installation Guide -- is provided'. The
manual also fails to mention a zoom display facility, that electronically
enlarges full-screen images recorded in the quad mode. The instructions do contain useful
information regarding a serial port, enabling the multiplexer to communicate
with or be controlled by a PC, however, on our sample this socket was blanked
off, though clearly there is provision for one to be fitted as an option.
OPERATION
Once the set-up routine has been completed, or no further menu
selections are made, the unit reverts to normal operation. The multiplexed VCR
output is independent of the monitor and can be safely ignored. During attended
operation the user can choose to view any of the four camera inputs by pressing
one of the selector buttons, or watch a sequenced display. In the replay mode
the operator can choose between a quad display, showing the recorded outputs
from all connected cameras simultaneously, full-screen display from one
selected camera, or a full-screen sequenced display of all recorded inputs.
Each image has the time and date imprinted at the bottom, of the picture, along
with the camera ident, and any alarm indications.
The alarm set-up options include the facility to switch the VCR
output from a sequenced display to one selected camera; at the same time it
will switch a time-lapse VCR into real-time mode. If more than one alarm is
triggered all or any of the cameras will be recorded in a new sequence. The
monitor output can also be configured to change when an alarm is triggered, to
show the output from the relevant camera, or cameras (in sequence).
PERFORMANCE
The 4Plex-QK is virtually transparent to the video signals which
pass through it. In full screen display mode there is no significant increase
in noise, reduction in definition or noticeable degradation, apart from the
inevitable reduced frame rate. This shifts the whole question of picture
quality onto the recording VCR. In the most heavily processed quad display mode
each of the four images are sharp, colours are accurately rendered and there's
plenty of detail.
OVERALL ASSESSMENT
There's much to commend the 4Plex-QK, it is reasonably
straightforward to set-up and very easy to use; performance is good and the
price is reasonable. Operationally it leaves only one or two things to be
desired. The most obvious omission is a quad display in the recording mode, as
it stands the operator can only choose between a single camera or a sequenced
display. It would also be useful to preset individual delay times for each
camera, though this is a minor consideration, and more than offset by the
flexibility of the system as a whole.
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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( R.Maybury 1995 0601
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