What is LED Display?

LED means Light Emitting Diode:

Light emitting diodes emit visible light when electricity is applied. Traditionally LEDs are created from two semiconductors. By running current in one direction across the semiconductor the LED emits light of a particular frequency (i.e. of a particular colour) depending on the physical characteristics of the semiconductor used. The semiconductor is covered with a piece of plastic that focuses the light and increases its brightness. These semiconductors are very durable, they contain no filament, require little power, are very bright and have a long life.

What is a programmable LED display sign?
Programmable LED displays are connected to a computer by cable, modem or via Ethernet. It is also possible to program an LED display sign by means of its own programming keyboard. ALPHA LED displays normally have both options. It is generally simpler and more efficient to program by means of a computer. Software designed especially for programming ALPHA LED displays is available. Most LED Displays are equipped with backup batteries to protect the data in the event of a power outage.  

What is the difference between a full matrix and character matrix sign?
On a full matrix sign, there are no spaces between the individual LED cubes. Each cube is directly adjacent to the cubes around it. This makes the sign look like a solid wall of LED pixels, which allows both text and graphics to be displayed. On a character matrix sign, spaces exist between the individual LED cubes, so only text can be displayed.

What is the difference between an indoor and an outdoor sign?
Indoor signs have smaller characters than outdoor signs, because the viewing distance is much shorter. Indoor signs do not have to be as bright as outdoor signs, because they do not have to be viewed in bright daylight. Outdoor signs are manufactured to withstand outdoor conditions of direct sunlight, and large temperature variations, rain, snow and dust.