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AURORA V816DC-NP 16-Channel Colour Muliplexer



It’s difficult to know where to start with the Aurora V816DC-NP. It’s best described as a 16-channel digital multiplexer, but that gives only the merest hint of what it can actually do. The V816DC-NP is most advanced model in the Aurora range, this particular version works with colour cameras and has full duplex operation, so it’s possible to review a tape, whilst the multiplexer continues to function. Eight channel variants are also available, and there’s a choice of colour or monochrome, and simplex or duplex operation on the 16-channel models.


In addition to the multiplexing function there’s a choice of multi-screen display formats -- for live viewing or during VCR playback -- starting with straightforward 2 x 2 (quad), 3 x 3 (9-screen) and 4 x 4 (16-screen) layouts. Various combinations of screen sizes are also possible, from a single PIP (picture in picture), to mixed full, quad, 9 and 16 screen displays, plus user-defined selections. Sequencing for the multi-screen displays and the PIP function can be set manually or selected randomly; camera dwell times can be set from 1 to 60 seconds. Each camera input can be assigned an ident and title and the display system generates time, date alarm and special function messages. The clock can be programmed to auto-correct for Summer and Winter time changes.


An electronic zoom facility allows any part of a full-screen image to be enlarged, up to magnification of X12.  A set of four direction keys work like a pan/tilt control, to define the target area. Full screen images can be frozen at any time, and detail closely examined with the zoom facility. Each camera channel has its own dedicated monitor output, the multiplexer also has two monitor outputs. The first one is designated ‘analogue’, this shows a simple camera sequence;  the other is the ‘digital’ channel, and this displays processed images, showing multi-screen and zoom effects plus camera and on-screen information.


There are numerous alarm functions, ranging from digital motion detection and hard-wire/contact triggers (one for each camera channel), to video loss detection. Various alarm responses are possible, they include front-panel LED indicators, video displays and an audible buzzer. The recording frequency of cameras associated with an alarm event is automatically increased, so it will be displayed and recorded more often during the sequence. All of the multiplexer’s functions can be controlled from the front panel buttons, a separate QWERTY-style keyboard, or remotely via a PC using the unit’s RS232/422 serial interfaces.


The multiplexer is housed in a discrete black metal box measuring 348 x 190 x 124 mm. Front panel controls comprise three banks of buttons, most of them having two or more functions. On the far left are the camera input selectors, which double up as display format selectors, (as shown by the graphic symbols between the two rows). To the right of that are four direction keys, used to control the electronic pan/tilt function as well as select and change items on the menu-driven on-screen displays. Next to that are four more buttons, variously concerned with menu selection and the electronic zoom.


On the back panel there is a bank of 36 BNC sockets, for the camera, monitor and VCR inputs and outputs, there’s also a pair of mini DIN sockets carrying a Y/C video output, for connection to a S-VHS video recorders. Three multi-pin D-sub connectors (two 9-pin and one 37-pin) handle serial communications and alarm connections.  The standard of construction is generally very good, and the device comes with a very complete accessory kit, that includes fixing hardware, blank plugs and 75-ohm terminators, for unused video channel outputs.


All functions are controlled from the menu-driven on-screen displays, which is fine except that unbeknown to us our sample had been configured for NTSC colour. This produced an unwatchable display when connected to a PAL monitor. Unfortunately the instructions make no mention of this possibility, and there’s only scant reference to changing the set-up. In any event this is of academic interest as the colour system setting can only be changed from the on-screen display. We only discovered the cause of the problem by luck, after connecting the unit to a multi-format monitor, to check whether the original monitor was faulty.


In spite of Vicon’s claims for user-friendliness the on-screen display system can be quite difficult to navigate. It’s easy to make mistakes, that can be difficult or time consuming to rectify. The main problem concerns the need to confirm every action by pressing the enter button, before and after any parameter is changed. It’s not a particularly  intuitive method, and it can become quite tedious. Some form of menu map in the instructions would have been welcome, and the supposedly helpful directions at the beginning of each section, shed little light, especially if you manage to get lost (which we did, frequently!). Here’s a typical example: ‘Keystrokes from the main menu for the restore setting must be edited to ¯,¯,¯,¯,¯, Enter, ¯,¯, Enter, ¯,¯,¯, Enter’. Work that one out...


Information detailing how to set-up the numerous sequencing options for the multi-screen and PIP display formats take almost one third of the 115 page instruction manual (not counting the addendum’s and additional software data supplements...). To be fair it does get a little easier with practice, but there are many options, variables and pre-set adjustments to contend with. Configuring a full 16-camera system and alarms could take quite a while!


Recording VCR set-up is relatively simple though, and the system contains a library of operating parameters covering most makes of VCR currently available, manual adjustment is also possible, for models not included.



In normal use -- following the initial set-up -- only the top-level menus need to be accessed with any regularity;  most other day-to-day functions, like camera and display format selection, can be made from the front-panel buttons.


The zoom facility is engaged by pressing the appropriate camera selector button twice, this can be on a live or frozen image. It works in a slightly unusual way and homing in on a particular area needs a fair amount of dexterity. The system cannot zoom and pan/tilt simultaneously; this involves repeatedly stabbing the zoom button, re-aligning the image, and zooming again, with the tendency to overshoot increasing as the level of magnification increases.


Alarms can be acknowledged manually or automatically, in the manual mode a buzzer sounds, which the operator has to cancel. The alarm output can printed out using the RS232 serial output.



Video processing takes place in the digital domain, and there is a slight textural change to the image; colour contrast is reduced slightly but noise levels and resolution remain largely unaltered during a video signal’s passage through the multiplexer.


The digital effects, in particular freeze and zoom, do result in a noticeable reduction in image quality. The increase in pixellation or blocking is not too bad below x6 magnification (as shown on the display), but at higher zoom settings fine detail is quickly lost. Multi-display and sequenced images are very clean, the update frequency is increased on camera channels where movement has been detected, which helps reduce the jerkiness of movement during live display or VCR replay.


Variable brightness, saturation and contrast allow the picture to be optimised for the viewing conditions.



In spite of our misgivings about the friendliness -- or otherwise -- of the on-screen menu system, the multiplexer works very well indeed. Features like the electronic zoom could be genuinely useful, though it has to be said, it’s no substitute for the real thing. However, the combination of basic functions --  multiplexing, multiple-display, alarm functions, and duplex operation -- and smooth, near faultless on-screen performance, sets this device apart from the competition.  



Design and design features              8

Circuitry and components                  9

Ease of installation and wiring    7    

Range and variety of functions            9   

Accompanying instructions                   7          

Technical advice and backup            ?     

Value for money                         8                            




Ó R.Maybury 1996 0507




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