Mis-connecting VGA

[Stuart91]

An interesting question came up today. We've got a customer getting a VGA line installed from the stage to the control point for their projection system. It will be used in two possible ways:

 

1) Someone on stage is running a presentation using their laptop and the VGA line will connect the laptop to the VGA switch at the back, and from there to the splitter and on to the projector.

 

 

2) The presentation is being run on a computer at the back, and the VGA line will connect a monitor on the stage to the splitter at the back.

 

 

So far so good. However, someone raised the point that it's not unforseeable that our (fairly novice) customers could get a bit mixed up and wind up connecting the VGA output from the splitter to the VGA output of a laptop. Obviously nothing will work, and they'll hopefully notice and change it over. However, I'm not sure if this is likely to cause any damage to either item if they do this.

 

Obviously, I'm not keen to try it out myself, but I'm curious if anyone knows what will happen. Is there any chance of damage?

[dunk_1984]

In practise this shouldn't harm anything, it just won't work. Someone may post some highly electronic response like you risk blowing such and such resistor, but really I doubt anything will happen. A suggestion, LARGE LABELS on the cables?

[paulglave]

In practise this shouldn't harm anything, it just won't work. Someone may post some highly electronic response like you risk blowing such and such resistor, but really I doubt anything will happen. A suggestion, LARGE LABELS on the cables?

Yes, I agree. No damage should occur... Try labels with very obvious pictures. Remember, people are stupid. Of course, you could make it even more confusing by using VGA line transmitters with cat5 connectors. Just think of the possibilities for complete lunacy there!!! Oh the joy.

[SmokeMonkey]

Forgive me if I'm being stupid - I'm only just up - but aren't VGA cables male/female?

[mac.calder]

No, between a pc and projector is a male-male cable (both PC and projector have female plugs) which is a pain in the rear, as it means you need to have genderbenders on hand when you want to join VGA cables into a longer run, or attach RGBHV tails (which are also typically male).

 

As for issues with VGA over Cat5, generally there would be less of a problem, because at least the transmitter and receiver would have their purpose printed on the case (ie "TRANSMITTER" or "RECEIVER") - Lunacy only ensues when they try and plug them into ethernet ports.

[paulglave]

No, between a pc and projector is a male-male cable (both PC and projector have female plugs) which is a pain in the rear, as it means you need to have genderbenders on hand when you want to join VGA cables into a longer run, or attach RGBHV tails (which are also typically male).

 

As for issues with VGA over Cat5, generally there would be less of a problem, because at least the transmitter and receiver would have their purpose printed on the case (ie "TRANSMITTER" or "RECEIVER") - Lunacy only ensues when they try and plug them into ethernet ports.

Trust me. It happens. That's why it's called lunacy. I've seen people try and get projectors working by plugging the usb lead in.

[Stuart91]

Trust me. It happens.

 

Certainly, people seem to assume that if it has the same connector, it must be compatible - thank goodness Neutrik speakons were developed.

 

The line will be used at some points for the monitor, at other points for a laptop connection. I'd far rather that they just had two VGA lines, but they came up with the request for the monitor after we had run the cable and don't want the installation expense again.

[blackbird]

Perhaps it would be best to install a switcher at the stage end also, with a pictures of laptop and monitor on it. If you've got a switcher at either end of the cable with appropriate pictures on the cables, then at least all they have to think about is "what have I got connected".

 

Of course you still have to hope that they don't think you can connect two computers together via VGA!!