Industrial LCD Monitors & Touchscreens

DVI and VGA connections

Cable for the image can be either VGA (15-pin) or DVI (Digital Video Interface, 24-pin).
DVI gives the highest image quality, but the computer must support the DVI interface. DVI Information (opens in new tab)
DVI-D (digital only)    DVI-A (analog only)     DVI-I (integrated, digital & analog)
DVI-DL: The connector also includes provision for a second data link for high resolution displays, though some devices do not implement this. In those that do, the connector is sometimes referred to as DVI-DL (dual link). Connector width: 37mm.

The DVI-I (24 + 4 pin connector) can transfer digital and analog signals which use C1 to C4 at the right.
This allows a VGA monitor with 15-pin D connector to be connected to DVI-I or DVI-A output with a simple plug adapter.
“Image phase adjustment” allows fine tuning of the image appearance.

The maximum length of DVI cables is not included in the specification since it is dependent on bandwidth requirements (the resolution of the image being transmitted).
In general, cable lengths up to 4.5 m (15 ft) will work for displays at resolutions of 1920 x 1200.
Cable lengths up to 15 m (50 ft) can be used with displays at resolutions up to 1280 x 1024.
For longer distances, to eliminate the video degradation, the use of a DVI booster or DVI extender is recommended. DVI boosters may or may not use an external power supply.

One nit (unit of luminance) is equal to one candela per square meter (1 cd/m²), used to quote the brightness of computer displays.

Candela: A unit of measurement of the intensity of light.
1 candela = 1 lumen/steradian. Part of the SI system of measurement, one candela (cd) is the monochromatic radiation of 540THz (near green) with a radiant intensity of 1/683 watt per steradian in the same direction.
Another way of putting it is that an ordinary wax candle generates approximately one candela in any particular direction.
A light source that uniformly radiates one candela in all directions radiates a total of 4pi lumens.
A 100 W incandescent lightbulb emits about 120 cd.
Steradian (sr) A unit of measure equal to the solid angle subtended at the center of a sphere by an area on the surface of the sphere that is equal to the radius squared: The total solid angle of a sphere is 4pi steradians.
1 Lux = 1 lumen/square meter, the illumination of a surface.

Resistive, Capacitive or SAW

Resistive Touchscreens are for applications where speed and accuracy are required, They are used primarily for point of sales and medical and industrial applications.
Resistive Touchscreens are versatile and pens, gloved hands or bare skin can be used to acivate the touchscreen.

Capacitive touchscreens need bare finger or wet glove to activate them.
The surface is tougher than that of resistive touchscreens.

SAW (Surface Acoustic Wave) Touchscreens are for applications such as information kiosks.
They are strong and are scratch and vandal proof.
Water, dirt and contaminants can’t get in.
They work even when glass is scratched.
The user must use bare skin or object that absorbs the sound waves to activate the touchscreen.