Projectors and Monitors

Projectors and monitors connect to a computer in one of two ways:

1. Analog VGA

An analog video cable has 15 pins. Take care when you insert this cable; it's easy to bend or break the pins. The connector can only be inserted one way. You shouldn't have to force it. The computer and the projector should both be off when you make this connection.

2. DVI (Digital Visual Interface)

The DVI connector pictured above can support digital or analog connections. A DVI connector lacking the four small rectangular pinholes at the left can only support digital connections. The connector can only be inserted one way. The computer and the projector should both be off when you make this connection.

Configuring the Computer

Making the physical connection between a computer and a projector is only half the battle. You also have to configure the computer to send its display signal to the projector.

Making the Connection on a Desktop Computer

On desktop computers, this is usually not a problem, because they have only one video output. To view the display on the computer's monitor and the projector simultaneously, you need a projector with a pass-through video port. You plug the computer into the projector, then plug the computer monitor into the pass-through port. For the best results, configure your computer's display to match the optimum, or native resolution, of the attached projector.

To configure the display on a Windows computer:

  1. Right-click the desktop and choose Properties.
  2. Click the Settings tab.
  3. For an SVGA projector, set the screen resolution slider to 800x600.
  4. For an XGA projector, set the screen resolution slider to 1024x768.

If your projector doesn't have a pass-through video port, you can use a splitter cable, but your display quality may suffer.

Making the Video Connection on a Laptop

Getting projectors to work with laptops can be tricky. A laptop has an internal LCD monitor, which is on by default. Its external display port is usually off by default. To get the projector to work, you have to enable that external display port. There is no substitute for reading the laptop's manual to learn exactly how to do that. If the manual isn't available, here are some steps to try:

  1. If one of the function keys (F1-F12 at the top of the keyboard) has an icon that looks like a pair of monitors, try holding down the laptop's Fn key and tapping that function key. This will cycle the laptop through its three display modes:
    1. Internal LCD only
    2. Internal LCD and external monitor
    3. External monitor only
    Wait 15-20 seconds between taps to give the projector an opportunity to detect the signal.
  2. If you always use a projector with a laptop, you may be able to use the laptop's setup program to enable its external display port by default. As the computer boots up, watch for the message that indicates which key to push to enter Setup.
  3. Some laptops have a Windows-based program that controls output to the external display port. For example, IBM Thinkpads come with a Presentation Director that sits in the computer's system tray. It enables you to choose external display modes from a pop-up menu.
  4. On a Macintosh OSX computer, select System Preferences from the Apple Menu, click the Display icon, then click the Detect Displays button to enable the external display port.

NTSC Video

Most projectors have NTSC (television) inputs. This enables you to connect a DVD player or VCR to the projector. You will get the best results if you use an S-Video cable to make the connection. Please note that S-Video does not carry sound, so you will have to connect a separate audio cable to the DVD/VCR and connect that to the projector, if it has built-in speakers, or to an external set of speakers.