Ask Dave
Please ask questions via Contact Us and Dave will post them below with the answer.
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Q
What is the wiring for the Techconnect VGA modules?
A
It’s on page 4 of the manual and I’ve copied it below…
| Phoenix Label | Signal | TC Cable Colour | Pin |
| R | Red | Red | 1 |
| Rs | Red Ground | Red Shield | 6 |
| G | Green | Green | 2 |
| Gs | Green Ground | Green Shield | 7 |
| B | Blue | Blue | 3 |
| Bs | Blue Ground | Blue Shield | 8 |
| H | Horizontal Sync | Brown | 13 |
| Syg | Sync Ground | Black | 10+5 |
| V | Vertical Sync | Yellow | 14 |
| SCL | DDC2B Bidirectional Data | Gray | 15 |
| SDA | DDC2B Data Clock | White | 12 |
| SH | Chassis Ground | Shield | Outer Shield |
Or if you’ve bought the modules seperately it will be printed on the box. If you’ve bought VGA cables from elsewhere your job will be a little harder because the colour of the wires aren’t standard. Red, Green, and Blue are always the same, but the sync and DDC cables are different so you’ll have to buzz them out with a multimeter.
Q
Does Vision offer “100v line” amplifiers?
A
In audio there are two types of amplifiers:
1/ “LOW IMPEDANCE” This is the type of amplifier used in your TV, car, home stereo, at a rock concert etc. This system typically operates where the loudspeakers present a 4 or 8 ohm load to the amplifier. Amplifiers have a wider frequency response, but this benefit of offset by the limitation that generally only up to 2 pairs of loudspeakers can be driven at a time. The speakers which work with a low impedance amplifier are cheaper because they don’t require a transformer to be added.
2/ “100V LINE” This type of amplifier is used when you distribute sound through many of loudspeakers throughout a building with one amplifier. They achieve this by interpolating the audio onto an 100v signal which is sent out the speaker cable. The speakers then use a step-down transformer built in to convert the signal for use. This technique allows loudspeaker signal to travel much further. The downside of this system is that the frequency response is narrower, making it only suitable for voice reinforcement.
The measurement of watts is completely different for each system. In simple terms a 100w low impedance amplifier is much louder than a 100w 100v line amplifier.
As most of Vision’s clients only require up to 4 loudspeakers per system, it was decided that the new class of digital low impedance amplifiers represented much better value, both in outright cost, and for the 100% efficiency now available with digital amplifiers. For example at rest true D-class amplifiers does not use any power at all unlike all other amplifiers which inherently use power all the time to keep the capacitors full.
Q
Does The Techconnect Amp come with a power supply?
A
Yes
It comes with a laptop-syle power supply which can be housed in a double-gang backbox, and a blank surround is available to cover it. Note if you do this you’ve got to push out the holes in the backbox to allow airflow to keep the power supply cool.
Q
Do I have to terminate “Chassis Ground” on a Techconnect VGA Modules?
A
No, but it’s good practice.
EU regulations are getting stricter about EMC (electro-magnetic compatibility) compliance – that is the way one device interferes with other equipment. For example your mobile phone will make that buzzing noise through an amplifier or speakers when it rings. That’s not allowed anymore. So proper grounding of your components allows each device to be “sealed” against interference.
Q
What is SCL and SDA on the VGA module?
A
Bidirectional signal which allows plug-and-play.
In other words when you plug a monitor into a computer the PC says “what resolution are you?” to which the monitor or projector replies “1024 x 768″, and the PC outputs at that resolution automatically. You don’t need to connect these cables to get an image, but it’s good installation practise to terminate them. Some cheap VGA cables won’t have pins 12 and 15 so don’t support this.
Q
I’m an end-user. Can I install the Techconnect Amplifier myself, or does an eletrician need to wire it up?
A
You can do it yourself.
The TC2-AMP2 comes with all the cables included so you can do it yourself. We do recommend these products are installed by professionals, but with the removable phoenix connectors it’s easy for a technical end-user to plug and unplug cables.
Q
Can the Techconnect Twist work with Smart USB Speakers?
A
No.
Audio over USB requires the full bandwidth of the cable, and as this is partly reduced when converting to run over CAT5/6 cable it will not work reliably. The chip-set could be changed to handle audio-over-USB, but this would reduce the maximum length to 10m which defeats the purpose for most applications.
Q
Does Vision offer a Scart module for the Techconnect?
A
No.
Vision used to have a scart module but it sold very poorly, so the best way around it is to take a blank module and cutout a scart-shaped hole so you can mount a scart connector into it.
Q
Does the Techconnect Control work with the Epson EB-460 projector and Sahara Skyline Electric Wall Screen?
A
Yes for the Projector. No for the Screen.
The Techconnect Control works with the Epson projector. A quick search on the screen you have shows that the remote control with that screen is RF. The Techconnect Controls are IR only so won’t work with the screen. Some projectors have a switching output voltage which is used to activate electric screens when the projector is turned on. The screen you have can be controled in this way but it seems that the EB-460 does not have this voltage output.
Q
I purchased a Benq 525st with a Vision TM-UST wall mount. Based on the wallscreen dimensions 2000x1513mm we reckon we need to get back to 1.79m. I cannot make out how far back the Vision TM-UST goes back and assuming its does not go back 1.79m what is the solution?
A
The maximum throw of the TM-UST is 1.5m, so I recommend using a ceiling mount.
I can confirm it is a 1.79m throw for a 2m wide screen. The TM-UST with extension pole goes out to 1.5m and I know a lot of people use the 525ST with this setup for smaller interactive whiteboards, but obviously it’s too far away if your screen is this big. Just a point of detail; the TM-UST has been replaced by the TM-ST which is essentially the same product but with a 1.55m pole as standard. So rather than having to buy the TM-UST and an extension pole, it all comes in one. This was done because 70% of people buying the TM-UST also bought the extension pole so it made sense.
The best solution is ceiling mounting. If you got your hands on a boom 1.8m long you’d have to stay it and make sure the wall is up to the job. I don’t know what your room is like, but this is what I’d recommend in this case.