Thursday, May 22, 2014

Digital Signage Tech & Spec: Standards for Outdoor LED Digital Signage

-Scott Hofheins

Unfortunately, there are no officially adopted standards for Outdoor Digital Signage specifications, at least in the traditional sense. However, there are certain industry terms and product specifications that are common between higher quality manufacturers. These have essentially come about due to the natural evolution of good designers and engineers, with the market response also playing a key role. While there are still certain “specs” that reflect more of a marketing strategy than actual product quality, good manufacturers tend to keep these to a minimum and can back up the talk, with the walk.

The Source
We discuss this quite often, but it bears repeating. Signs designed, produced and supported in the USA will provide much less risk for your money, and a significantly better experience over the lifetime of the sign. There are many companies claiming to be manufacturers, who source a very large portion, if not their complete sign package from overseas suppliers. These companies function more as a distributor, rather than a real manufacturer and tend to rely on the overseas supplier for design, engineering and development.

Make sure the manufacturer for your LED sign has a real and active factory in the USA with software and hardware development staff in-house. The support staff, warranty program and parts inventories should also be local and streamlined. Without this, you run the risk of a sub-par product, with limited support and a warranty in words only.

The Matrix and Pitch
Outdoor Digital signage uses a “matrix” of individual LED’s grouped into pixels to create an image, or text on the display. An important factor in how good your LED sign will work is the number of pixels the face contains. This is affected by 2 major specifications: The “Pixel Matrix” and the “Pixel Pitch”.

“Pixel Matrix or just “Matrix” represents the number of pixels high and the number of pixels wide the LED display contains. This can vary according to the “Pitch” of the display, how tightly packed the pixels are to eachother, measured in millimeters (mm).

For example, a 16mm sign and a 20mm sign can both be produced at approx. 4 ft x 8 ft. But the 16mm will have a better image quality because more pixels will fit in the same area. This is a common cause for confusion with potential LED sign buyers by itself, but sometimes made worse by marketing jargon and intentional misinformation.

While there are some larger pitches still available (32mm and higher), used for large text based signs, most organizations will fall at 16mm - 25mm. The prices increase significantly after 16mm, but if you're looking at getting a sign for viewing close, pedestrian traffic, the tighter pitches are the way to go.

  • 25mm
  • 20mm
  • 16mm
  • 12.5mm (usually marketed as a 12mm)
  • 10mm
  • 8mm
  • 6mm

When comparing pitches and the matrix for products, remember to compare apples to apples and use the actual physical pixel pitch and matrix of the display. There are some great enhancements like virtual pixels that provide a better image on 16 - 25mm displays, but they should be treated as a separate specification/benefit.

The Colors

  • Full Color / RGB: These signs use one or more Red, Green, and Blue LEDs per pixel. These are the necessary combination to accurately produce full color content for text, images and video/animations. The number of colors these displays claim to produce can vary, and are sometimes abused. Anything between 16.7 million - 281 trillion colors is standard. Numbers above this tend to be over inflated, or measured in a different way to produce a better looking specification, but will have little effect on the actual display.  
  • Single Color “Shaded” or “Grayscale”: These type of signs are single color, but the LED’s can dim independently to provide different shades of a single color, typically Red or Amber. The current standard is 4096 shades. Avoid signs that only show 256 shades.
  • Tri Color: Not to be confused with actual full color signs, these displays have one green and one red LED per pixel, when combined together will produce an amber color. They are typically used to produce colored text only, but are sometimes marketed as a cheap alternative to a full color LED sign. However, the color quality on images and video is extremely poor, if supported at all.
  • Monochrome/One Color Only: These are the traditional text only signs that were popular in the past. They produce only one single color, usually Red or Amber (yellow). They don’t draw as much attention from viewers these days, and their use and availability has significantly declined in the outdoor market.

The Control System
There are two main standards for LED sign controllers. IPC (industrial PC) and Embedded Controllers. Each approach have pros and cons for both the end user, and the manufacturer, but I have always recommended IPC controllers.

  • IPC controllers: These are a commercial grade computer, running a standard operating system. They tend to be more powerful than Embedded systems and support higher quality content and smoother animations and transitions. They generally have more storage capacity, and provide more options for customization and long term updates and scalability, but tend to add a bit more cost to the systems.

  • Embedded controllers: These are printed circuit boards that operate using a proprietary firmware, rather than an full operating system. They offer less processing power and lower frame rates, but are popular with some manufacturers for their closed system approach. They are less expensive than IPC’s but harder to implement custom solutions and harder to keep updated over the lifetime of the sign.

The Software
It’s easy to forget the software when looking through spec sheets and product information, but this is something LED sign owners interact with on a daily basis. It’s worth the effort to verify you will be getting the complete package. Some standards to look for.

  • Developed in the USA: Unfortunately a large percentage of overseas signs are provided with extremely unfriendly software provided by the foreign supplier. The interface is difficult to use, and includes poorly translated documentation. Software developed in-house, in the USA focuses on the needs of the user, and takes current software standards into account. Don’t be afraid to dig into this, and make sure your getting a real software product, not a “skinned” version of the foreign suppliers software.
  • Local and Cloud Based Options: You should have the option to either FULLY control your LED sign locally, or provided software from the cloud. Local control is useful for mobile signs, sites without internet access, or in special applications like scoreboards. Cloud based solutions should provide complete control of your sign over the internet, not just certain aspects of the sign.
  • Scheduling Features: The scheduling interface should be easy to use, but still allow advanced options like media groups, scheduling for different days of the week and time of the day, and the ability to play message based on external conditions like temperature. Avoid software that only provides a single playlist of files. You should be able to add multiple files, to play on multiple dates and times, without limitations on how far you can schedule out.
  • Content Creation and Editing: The software should allow you to create an edit your own messages, add a wide variety of file types for playback on the LED sign, as well as a general content library for your own use. Additionally, software that will provide access to a content creation service is highly beneficial.

The Case and Internal Components

  • Manufacturers should have complete control over their case construction, to maintain the quality and weatherability of the sign. Nothing will kill an LED sign faster than water intrusion, or overheating due to design or production flaws. The manufacturer should be able to provide cases with or without a border, and offer custom fabrication options for unique applications.
  • The case should allow easy access to the components. The current standard is a front access design, where LED modules are easily removed from the front of the sign. The internal components should be easy to replace, and have standardized locations and mounting hardware. They should be designed, stocked, and fully supported in the USA by the manufacturer directly.

Specifications are important when comparing LED signs, so make sure you are getting accurate numbers, and comparing apples to apples by digging deeper and asking the right questions. Do your own research and make sure your getting the whole package, for a reasonable price. Look for a sign provider who has your best interests in mind, and uses a manufacturer who does the same.


I hope this post has been informative and helpful. As usual, I welcome ALL constructive comments. Please feel free to comment and add anything I’ve missed, or additional tips you may have regarding this topic. Please visit for many other resources, white papers, and of course: Great looking LED Signs!

**All posts/thoughts/writings are strictly the viewpoint of me and me alone and do not reflect nor speak for Vantage LED’s beliefs, attitudes, thoughts, etc. unless specifically stated.

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