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Despite the huge inroads digital video processing has made into virtually all corners of the video surveillance market camera multiplexers are still widely regarded as an overly exotic and expensive technology for many small-scale installations. Dedicated Micros is hoping to change a few minds with its new Sprite Lite 4-way multiplexer, a low-cost design targeted specifically at retail and consumer applications.


Sprite Lite SLDX4C is very closely related to several other multiplexers in the DM range but it is more than just a stripped-down 9 or 16 camera unit and incorporates a number of advanced features, which we’ll come to in a moment, but first the basics. It’s a full duplex design allowing simultaneous recording and playback (with supporting hardware), display options include single camera, sequence, picture-in-picture and quad. On a single camera display there’s a 2x zoom facility with electronic ‘pan and tilt’ and it has a password protected setup menu. Each of the 4 input channels can be individually enabled and have associated external alarm inputs and user-set activity detection.


In response to end-user and installer feedback DM has incorporated several new features. Making its first appearance on this model is fast video processing giving a ‘live’ quad display, there’s camera editing, for including or excluding cameras from the recording sequence and monitor displays, it has selectable text (large, small or none) on the VCR output channel and an optional wired remote control facility. DM has also tweaked the operating control system software, making some operations slightly quicker, users now have better control over the spot monitor display and the unit has a camera input failure detection with relay output and an on-screen alert.


From the outside it looks conventional enough. The front panel is very similar to its stablemates with a bank of blue-coloured camera selector buttons on the left side. In the middle are three mode indicator LEDs, and on the far right there are five multi-function buttons that between them control mode selection, display format and call up and control the menu-driven on-screen displays. The rear panel comprises a bank of 12 BNC sockets for the camera inputs and loop-throughs, VCR in/out and monitor (spot and main) outputs. Three plug-in connector blocks carry alarm inputs and outputs, VCR sync/switching and the two relay connections (alarm and camera fail). Two RJ11 telephone type connectors are used for DM’s proprietary C-Bus communications system and the optional remote control and power is supplied to the unit via an external mains adaptor using a round multi-pin socket on the far left.


Inside the heavy gauge steel case there is one rather lonely looking PCB, it’s smothered in surface mount components and microchips and since there is only one external connection (all of the I/O sockets are mounted on the PCB) from the main board to the display and buttons on the front panel, mechanically it should be very reliable indeed.



Installation is about as simple as it can get and we do not anticipate any problems. Setup is another matter, getting the on-screen display to appear isn’t difficult -- hold down the Mode button on the far right -- but moving around within the menus and making changes can be tricky at first. It’s actually not that difficult once you’ve got used to it, but expect it to take a while as in spite of any improvements it’s still not very intuitive.


For some odd reason the menu display opens with alarm and camera status, indicating current connections. Page two looks like it should be the opening page since this deals with the time and date setup, operating language and information about the system software. Page 3 is concerned with VCR setup; options include DM or Robot replay formats, VCR type (time lapse/real time/user defined), VCR recording speed, alarm record speed and VCR text size. Menu page 4 is one of the new features and selects which cameras will be recorded, page 5 is for selecting which cameras are available for display. Menu page 6 covers system options with items for setting up a password, recording and spot monitor locks, resetting the unit to factory defaults and enabling the optional remote control facility.


Camera setup is on page 7; this includes a title facility (1-line x 12 characters), camera termination (on/off), camera type (colour/mono/auto) and alarm input (normally open, normally closed & off). The last menu, page 9, is for the camera activity setup. There are 5 sensitivity levels (indoor high/low, outdoor high/low and very low), the setup display for the activity grid (16 x 8 targets) and a switch for a ‘walk test’.



One of the first things you notice about Sprite Lite is jitter-free real-time video in quad display mode. In addition to looking a lot better the faster video processing also means more information ends up on the tape, giving sharper and smoother pictures during replay. There is no perceptible increase in picture noise, any significant changes in colour rendition or processing artefacts on the video outputs making the multiplexer largely transparent to the signals passing through it. 


Considering what we’ve already said about performance and taking into account the price it might seem churlish to grumble but we do think a couple of items are missing. The first is variable camera switching/dwell times – an odd omission in view of the unit’s generally impressive specification.   We would also welcome some way of manually positioning on-screen text, as it stands camera titles are fixed and set against a black background, which could potentially obscure important detail. By the same token it would also have been useful to move the clock date and mode displays from the bottom of the screen to a more convenient location



As far as performance is concerned the SLDX4C gets a very clean bill of health and in some respects – the fast video processing speed and ‘live’ quad displays spring to mind – it actually works better than a lot of mid-range and top-end multiplexers. There is some room for improvement – a few minor tweaks to the operating system and on-screen displays wouldn’t go amiss – but that doesn’t detract from the fact that end-users with small-scale systems now have an affordable and more flexible alternative to crude switching systems, with all the operator benefits and enhanced coverage that multiplexers can provide.



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                         ****                          



ă R. Maybury 2000 0208



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