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MPX 9104 MONO MULTIPLEXER
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WHAT OUR EXPERTS SAY...
These days there’s no shortage of well
specified colour, quad-display multiplexers available to installers and
specifiers. In contrast there are comparatively few monochrome models to choose
between. Clearly the falling cost of colour cameras is one reason for the
market bias, but it’s easy to overlook the fact that the majority of surveillance
cameras and systems remain firmly entrenched in monochrome technology. There is
a still a very healthy demand for black and white peripherals and ancillaries
however, something that Robot UK have sought to address with the new Appro MPX
9104 multiplexer.
The price is remarkably competitive, though
the specification is by no means basic. Up to four inputs can be combined, for
simultaneous display and recording. It has a range of live display modes,
including quad and single camera. Duplex operation means it can record, and
display images at the same time. A built-in character generator and clock
displays the time and an ident for each channel. Alarm facilities include video
loss and contact closure sensing for each channel. It has four programmable
motion detectors, one for each input, these are used for alarm activation or
activity detection. Alarm events are signalled by an on-board bleeper. The
display has a resolution of 1024 x 512 pixels, with 256 greyscales, and all
camera synchronisation is carried out internally.
The Taiwanese-built MPX-9104 is housed in a cream-coloured,
standard 19-inch rack mountable case measuring 420 x 200 x 44.4mm. There are
only eight buttons on the front panel, each with an indicator LED. The first
three, ‘Select’ ,‘VCR’ and ‘Sequence’, have dual functions, firstly to set the display
position during VCR replay, switch to VCR replay mode and engage auto
sequencing. They’re also used to enter the set-up mode, and control various
functions on the on-screen displays, which we’ll come to momentarily. The next
button is for switching between the quad and full-screen display mode; the four
remaining buttons are for channel selection and cursor control for the menu
functions.
Around the back, on the back panel, there are
11 BNC sockets; 8 of them are for the four video inputs and their associated
loop-through outputs, the other three are for the monitor output, VCR input and
output. Next to each video inputs there’s a rotary gain control with a range of
+/-2dB; the video output is unaffected. There are two 9-pin D-Sub connectors;
the upper one is for a remote control operation, using an optional RC-5004
keypad, or via PC, using RS-232 serial communication link. The lower one is for
the external alarm inputs, with provision for normally open or closed contacts.
Also on the back panel is the main on/off switch and a socket for the external
24 volt mains adaptor.
OPERATION
Pressing the select and VCR buttons
simultaneously brings up the first of five pages in the menu display. This covers
setting camera title or ident, video loss alarm enable/disable, dwell time (0
to 99 seconds), video output (live or multiplex), time and date setting and
display mode. The second menu page deals with alarm settings. This includes
sensor type (N/O or N/C) and sensitivity, alarm hold and duration, VCR type, operating
mode and record time. Menu page 3 is concerned with the device ID code and control
lock, RS-232 configuration, bleeper enable/disable, relay output and video
motion detector set-up for each channel. The latter, when selected, displays a
matrix 12 x 24 targets. The area of sensitivity is defined by switching targets
on or off as required. Sensitivity can be set in a range 0 to 99. The final
menu page is an alarm activity log, that lists the last 64 alarm events, along
with time, date and type of activation.
When a video loss or external alarm is
triggered the unit responds by sounding the bleeper, the corresponding channel LED
indicator starts to flash and a warning message appears on the video display. The
last image is frozen, in the case of video loss. If the motion detection system
is triggered the word ‘motion’ appears on the screen and the sequencer
increases the repetition rate of the associated channel in the VCR output.
The instructions contain all of the
information an installer is likely to want or need. They’re fairly well-written
too, and mostly easy to follow. The set-up routines are reasonably simple;
accessing some functions can be quite time-consuming, however, since they’re only likely to be set once, following
installation, it’s not a major problem.
PERFORMANCE
Image quality is very good indeed. Evidence
of the heavy-duty digital video
processing going on behind the scenes is evident in the jerky motion artefacts on
full and quad-screen displays but resolution remains impressively high. There
is some loss of detail and the contrast range is narrower but it is negligible,
compared with the losses that occur when the image is recorded to tape. They’re
virtually undetectable when compared with an un-processed off-tape recording of
the same scene. Camera switching is very clean with no disturbance at the
switching point.
Replay of multiplexed recording is very
clean, though much depends on the capabilities of the VCR.
The motion detector system is most efficient,
though it can take some time to get the correct sensitivity level, especially
on an outdoor scene. The audible alarm is rather quiet though. If an external
sounder isn’t used it could go unnoticed in a noisy control room, though the
on-screen and front-panel indicators should ensure an activation will not go
unnoticed for long.
OVERALL ASSESSMENT
The designers have struck a very good balance
between features, performance and cost. The MPX-9104 works extremely well. We
don’t anticipate any problems with installation or set-up, and once programmed it
requires very little operator attention. A useful piece of kit that fills a
noticeable gap in the market.
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 1997 1509
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