The two minute guide to sizing a digital signage network9 February 2011
ONELAN gives readers of TFA a run through the key factors when surveying a requirement for a digital signage network. It’s easy when you know how.
A digital signage network is a collection of digital signage media players controlled from some central location via a Local Area Network (LAN) or a Wide area Network (WAN).
Provision is generally made for a media scheduler that allows the collection of media players to be controlled from a central location. Some solutions also make provision for local operators to customise the media displayed. A network of players will generally require a Network Management System to allow the health status of the entire network to be observed from a central point.
Digital signage networks deployed in the retail sector for the purposes of advertising may also require a means to provide an audit trail of the media played.
Sizing up a digital signage installation
The key factors when surveying a requirement for a digital signage network are:
Number of displays – an installation factor.
Number of players. One ONELAN Net-Top-Box provides one output (audio and video). The Net-Top-Box can drive any number of displays using Video Distribution Amplifiers (VDAs). VDAs can be sourced from a variety of third-party vendors. They occur in two types:
VGA+Audio-in to VGA+Audio-out. This type of device requires VGA+Audio cables to be installed to all displays. These cables can be very difficult to install and field terminate.
VGA-over-CAT 5. In this scenario, the VGA+Audio signals are converted in order to be able to travel over low cost (and easy to terminate) CAT 5/5e/6 structured cabling at a transmitter device. A receiver at each remote display is then used at the far end to convert back to VGA+Audio.
Distance between players and displays. A judgment has to be made as to the most cost effective deployment of players (Net-Top-Boxes) and VDA type. Both VDA methods have distance limitations in the 100M to 300M range. However, the Ethernet network connectivity required for the control of Net-Top-Boxes is not generally limited.
Geographic location of the players. If all the players are located in the same campus, there is generally not a problem. If the players are located around a WAN, there will be bandwidth and access permission factors to consider.
User requirement for Media Display
Show the same media on all displays – Use VDAs if distance limitations allow – see above. If more than one Net-Top-Box is required, make use of the Net-Top-Box’s built-in Channel Manager facility to replicate the media on one site to a number of other sites.
Show the same look-and-feel on a set of Net-Top-Boxes but allow local customisation – eg a receptionist’s message. Use Channel Manager and the Net-Top-Box’s built-in Ad-Hoc facilities.
Show different media on sub-Channels with a collection of Net-Top-Boxes but controlled from a single central location. Use the Net-Top-Box’s Channel Manager facility with its in-built Advanced Ad-Hoc facilities.
Network management. Any collection of networked devices requires a network management solution in order to expose the operational status of the network appliances and links. The Net-Top-Box is no exception. ONELAN provides the Digital Signage Manager (DSM) – an application-specific network management solution for use with Net-Top-Boxes. It is recommended for any network of five or more Net-Top-Boxes.