Digital signage is a form of electronic display that shows information, advertising and other messages. Digital signs (such as LCD, LED or plasma displays) can be found in public and private environments, such as retail stores and corporate buildings.

Advertising using digital signage is a form of out-of-home advertising in which content and messages are displayed on digital signs with a common goal of delivering targeted messages to specific locations at specific times. This is often called "digital out of home" or abbreviated as DOOH.

The benefits of digital signage over traditional static signs are that the content can be exchanged more easily, animations can be shown, and the signs can adapt to the context and audience, even interactively. Digital signage also offers superior return on investment compared to traditional printed signs.

igital signage relies on a variety of hardware to deliver the content. This is typically a display screen, player server and a content management server (sometimes both the same thing), over an infrastructure (dependent on the location of these pieces of hardware).

Displays

Digital signage displays may be LCD or plasma screens, LED boards, projection screens or other emerging display types like living surfaces or Organic LED screens (OLEDs). Other, less traditional technologies for digital signage exist, such as 'holographic displays', water screens and fog screens. However, these are typically used for smaller one-off installations rather than large networks.

Rapidly-dropping prices for large plasma and LCD screens have led to a growing increase in the number of digital signage installations. Another price-related benefit that is allowing a larger group of businesses to install digital signage is the increasing availability of newer LCD and plasma display brands in the market. Many locations have opted to forgo more expensive brand name displays for more affordable displays from less well-known companies.

A recent study shows that there is a statistically significant relationship between price and the display size. The same study also shows that there is a significant relationship between price and brand name. These two variables account for 77% of the price in displays.

Content playback and management

Content is played to the displays of a digital signage network from at least one player machine. Various hardware and software options exist, providing a range of different ways to schedule and playback content. These range from simple, non-networked media players that can output basic loops of MPEG-2 video to complex, N-tier players networks that offer control over many displays in many venues from a single location. The former are ideal for small groups of displays that can be updated via CD-ROM or USB flash drive, while the latter allows digital signage network operators to either push content to many players at once or have each player pull content from a server as needed.

Developments in Web services have meant the APIs for some digital signage software now allow for customised content management interfaces through which end users can manage their content from one location, in a way which suits their requirement.

The recent introduction of free digital signage software may further expand the pool of potential users of this technology.

Network infrastructure

Unless the player server is located at the display, there is usually a network connecting the digital signage displays. The video (and possibly audio) is distributed to the displays through a series of wired network connections (such as Cat 5 cables) or wireless connectivity through the use of wireless adapters. When distributing through anything other than a video/audio cable, the signal will need to be converted with transmitter and receiver baluns.

To manage a network, a management server is usually required. This can be located anywhere, so long as it is connected to the digital signage network. New content will be managed and organised here, while the actual content itself is stored and played on the player servers.

Digital signage networks can either be closed or open to the Web, which will affect how the content on the screens is updated. For closed networks (without Internet access), updates need to be done locally through USB sticks, DVD drives or other 'on-site' updates. Open networks (with Internet access) can be updated remotely and stream data from other Internet sources (such as RSS feeds). The availability and type of Internet access (wireless, broadband, etc.) depends on the location and client.

Technologies such as IPTV allow digital signage to be used as a method of broadcasting. The content is played according to instructions provided by play lists controlled by the digital signage system content management server. Convergence between digital signage and broadcasting allows for real-time distribution of broadcast sources (TV) on a narrowcast network (digital signage).