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As CCTV technology becomes ever more sophisticated it seems that system designers sometimes loose sight of the basics and forget that in the end human beings are going to have to install and operate these devices. Fortunately user friendliness is high on the list of features on the new Gyyr range of Digiscan Pro multiplexers



Digital video technology can be a double-edged sword. On the one hand it gives system and component designers unprecedented opportunities to incorporate new and novel features; the downside is that too many functions and facilities makes the installer's and operator's lives even more difficult, sometimes to the extent that security could be compromised. There is a balance to be struck and Gyyr seem to have managed it with its latest range of Digiscan Pro multiplexers. They make full use of all that the latest video processing microchips have to offer but installation, set-up and day to day operation harks back to an earlier age, when you didn't need a degree in rocket science to keep an eye on things…


We have been looking at the DSP-16 16-channel colour multiplexer, a black and white version is also available and there is a 9-channel model (also colour or black and white). The core feature is full duplex processing, so the unit can continue normal multiplex recording operations whilst simultaneously replaying tapes from a second VCR (though this would entail some re-cabling as it only has one set of VCR connections). All camera inputs have an associated video motion detection (VMD) function, which, when enabled, increases the recording rate of associated cameras when activity is detected. Additionally each camera can be linked to an external alarm input for camera homing and activity following.


Monitor display format options during record or playback are full screen, quad, 3 x 3 and 4 x 4 with electronic 2x zoom on a single screen. A programmable timer enables separate camera sequences to be created for day and night time operation, the multiplexer generates on-screen displays and user-programmable camera idents and most programming and operational functions can be remotely controlled from a PC. A covert recording option stops an operator viewing nominated cameras and an advanced networking capability, using an RS 485 serial port, allows the multiplexer to function as part of much larger, centrally controlled system.


The extensive list of advanced features is not immediately obvious from the front and rear panels, in fact it is a classic 'black box' with few external clues as to it's real capabilities. The box in question is indeed black and made from steel; it measures 437 x 298 x 450 mm. On the rear panel there are 36 BNC sockets, that's one for each camera input and it's associated loop-though, two for the VCR input and output, and two for the monitor outputs. Monitor 1 is the main operator display showing processed digital images, monitor 2 acts as an analogue spot monitor. The other rear panel connections are a female 9-pin D-Sub for RS-232 and RS-485 serial communications, a 25-pin D-Sub for alarm connections and switching pulse input from the recording VCR (for automatic camera sequence speed synchronisation), and a DC input socket. Power is supplied by an external 230VAC to 12VDC mains adaptor module.


Moving on now to the front panel, the layout is strikingly simple. All control functions are accessed by a series of buttons on a thin flexible membrane. The right two thirds of the panel are taken up by the 16 camera selector buttons, each one has an associated LED indicator that glows green, to show a camera is selected, and red to show it is has been selected. On the left side of the panel there is a group of six buttons for setting or selecting record/playback mode, VCR view, zoom, spot monitor and display format. On the far left is a set of four arrow keys which have various functions, from navigating the on-screen menu to selecting a different view in the zoom mode.


Before we move on to installation and set-up a quick look inside the box. In fact there's not much to see, there is a single glass-fibre PCB covering around three-quarters of the bottom surface of the case. The board is mostly populated with surface-mount components and microchips and is very neatly laid out. There are no obvious late 'mods' or any other indications of work in progress, an encouraging sign that suggests all of the bugs and wrinkles have been ironed out. The only internal wiring is a set of short ribbon cables for the input and output sockets on the back panel, and the front panel membrane switches.


Basic operation is very straightforward, to the extent that Gyyr have the confidence to include a 'Quick Start' sheet in with the instructions. It's the sort of thing you get with domestic video recorders -- intended for those who simply want to get the system up and running in the shortest possible time and can't be bothered to wade through the manual. By the way, Gyyr also supply the complete manual on CD-ROM, for PC and Mac users, along with the necessary Adobe browser software.


The on-screen display normally contains the time and date, camera ident, VCR recording speed and any alarm or status indicators. Access to the main menu and set up controls can be restricted using a simple two-key sequence that locks the appropriate front panel controls. The set-up display is accessed by pressing the 'P' button on the far left of the front panel, this blanks the picture and brings up the main menu offering seven choices: time and date setting, display options, system options, alarms, switcher programming, serial ports and system data. Items are selected using an arrow that scrolls up and down, using the arrow keys. The Time and Date sub menu covers clock setting and it also has facilities to switch between 12 and 24 hour time and rearrange the date formats. We carried out a standard Y2K rollover test and the clock/calendar responded correctly to the changeover and also recognised the fact that 2000 is a leap year.



The Display Options menu includes settings for the on-screen text colour, text position, language and provision for creating a site ident. System Options covers setting up the type and characteristics of the recording VCR, configuring the display (camera dwells, nominating a covert camera that can’t be viewed by the operator etc.). Other System Option sub menus are used to set up the VMD pattern for each camera (a grid of 24 x 12 individually switchable targets with 5 levels of sensitivity); there's an option for setting video terminations for each input (75 ohm or High Z), switching the keypad beeper on and off and enabling or disabling VMX (vertical interval encoding for improved read/write compatibility).


On the Alarm sub-menu there are options to review and clear the alarm log, set individual inputs to normally open or normally closed configuration, set video loss alarm, program day and night switching modes and specify how alarms are displayed, during an event.


The Switcher Programming menu has sub-menus for timer mode operation, setting up separate day and night sequences and creating camera titles. On the serial Ports menu there are the comms protocol settings for the RS-232 and RS-485 ports (baud rate, parity, mode, code, flow control, address etc.), and finally, the System Data menu, which contains information about software and serial numbers etc.


System set-up is very simple indeed; it's almost foolproof, though not quite and there is the (hidden) option to perform a master reset and return all settings to their factory defaults. Menu access is fairly intuitive and as far as we could see it has no hidden surprises. The only time consuming operation is setting the activity targets in the VMD mode, and camera sequence programming but it is certainly no worse than comparable systems in this respect. The VMD activity grid responds to movement whilst it is on screen, helping to identify areas of the image that could provide a false alarm.



What goes in comes out, in other words the multiplexer is largely transparent to the video signals going into and out of the unit. The signals that emerge and are displayed on the monitor or recorded on the VCR travel through largely unscathed -- aside from the inevitable reduction in frame rate due to multiplexing/multi-screen display. There is no additional noise, loss of resolution or colour fidelity. Camera switching -- manual or sequenced -- is precise and glitch-free with no on-screen disturbance. There is some quality loss in the zoom/enlarge mode but this is quite normal and there is no suggestion that this is in any way a substitute for an optical zoom or pan/tilt mechanism. In fact video performance is close to the textbook ideal, the only small surprise is the sensitivity -- or rather the lack of it -- in the video motion detection system. At the highest setting the system responds comparatively slowly to changes in scene illumination or contrast -- brought about by movement. In practice this means it tends only to react to quite large objects. The benefit is fewer false alarms but the downside is that it may miss some kinds of activity.  



Even though the DSP-16C employs cutting-edge technology it somehow manages to look, feel and function like a product that been around for a long time. Part of the reason for that is the elegantly simple user interface and almost foolproof menu system, which gives access to key facilities but avoids delving too deeply into functions that are adequately handled by the microchip minions. Flexibility is another big selling point and the system's ability to operate in a stand-alone role, or as part of a larger networked system will make it a lot of friends amongst specifiers and end-users. Video performance is excellent and the high level of processing adds nothing, and takes nothing away from the camera or VCR inputs. The activity detection system isn't going to set any new records but its apparent insensitivity will doubtless reduce the number of spurious alerts. The DSP-16C exudes a reassuring sense of quality and reliability, there are no hidden surprises -- nasty or otherwise -- it does the job, and does it well!




Power supply              230 VAC 50Hz

Weight                        4.3kg

Dimensions                 437 x 298 x 450mm






Product design 9

Build quality               9

Ruggedness                9



General functions            8         

CCTV functions            9         

Ease of use                 8

Instructions                8

Manuf. support            8                     



Video quality              9

Switching                    9

Audio                          n/a


Ó R. Maybury 1998 0712



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Copyright (c) 2005 Rick Maybury Ltd.