Last updated on July 11, 2016

Introduction to Signs

Signs helps you create scalable digital signage apps with images, videos, video streams, and widgets, that are easy to build, schedule, and manage, for single-display deployment or multi-screen integrations across various industries. These apps can be deployed both horizontally or vertically on display devices such as LCD panel touch screens, HD video walls, plasma TVs, LED message boards, or mobile devices, via digital media players or browser-based devices, over the cloud and distributed networks.

The following are sign types you can create in Signs:

  • Basic: The Basic sign has a simple workflow to create fullscreen playlist-driven signs in landscape or portrait mode. The functionality of the media zone widget is brought forward and integrated into the very first view of the app, providing you immediate access to the content playlist from the Overview page.

  • Advanced: The Advanced sign allows you to build both passive and interactive signs with content-rich signs using a blank canvas or built-in templates, with multiple layouts, and widgets that include live feeds of weather forecasts, news headlines, sports updates, stock prices, business news, traffic reports, and such.

    You can also add actions based on event-driven scripting to your sign, that are triggered when an event occurs in the system, sign, layout, or widget. You can then choose to schedule the layout, widget, or app to run at a specific time, duration, or location.

  • Data Only: A Data Only sign contains only data-source widgets such as media playlists, tables, calendars and such. Data Only apps do not have a Visual Editor or visual representations, but the data sources are still available via API and via media-zone linking. Thus you can leverage this app by creating separate Data Only signs which hold playlists without complex layouts, widgets or event actions, and then link those playlists into actual on-screen Signs.


The following are the key features in Signs:

  • Layouts - A layout is a canvas for building your app with various content and widgets. A Sign can contain one or multiple layouts, with content organized and presented in various styles, formats, and locations on the display screen.

  • Visual Editor - The Visual Editor is the primary tool to build and design signs in Appspace, with drag-and-drop layout editing capabilities and several preview modes.

  • Widgets - Widgets, added to a sign’s layout, provide dynamic visual presentations with real-time data sources such as weather information, event calendars, and RSS feeds.

  • Scheduling - Scheduling within a sign allows the display of the desired playlist content or layout at scheduled dates or times for the set duration, according to priority levels.

    You can also set schedules that can display selective media assets that are defined and filtered with advanced tagging rules.

  • Event Actions (Action Scripts) - Advanced XML-based scripting capabilities allow designers and developers to apply custom actions that respond to user interaction and widget data or media updates when an event is triggered.

  • Sign Templates - Appspace provides customizable default templates with built-in features and functions, in the Sign Templates Library.


Signs Framework

An XML document with display, behavior, and schedule details, created automatically when you create an app, provides the framework to a Signs sign. The organization of the XML document is as follows:

Sign – the root of the document is the signs Node. This contains sub-properties such as the sign ID, name, and
              resolution.

  Schedules – every app by default contains one schedule that is active all the time. If layout scheduling is enabled, each layout
              playlist will be contained within a schedule.

    Layouts – each schedule contains a collection of layouts.

      Widgets – a widget is the basic building block of an app. Widgets provide the look and feel of the layout as well as the
                functionality of an app. Certain widgets such as the Media Zone widget can link their content to other widgets
                in different apps.

        Visual – determines the look and feel of the widget on the layout.
        Content – defines the data set or media files that populate a widget.
        Actions – defines any user-defined action scripting on the widget to exhibit dynamic and interactive behavior.
        Permissions – defines a list of rights for specific users to view or edit any properties of the widget.

Sign Properties – List of system and user-defined key value pairs for non-visual app properties such as screensaver time.

When the XML file is downloaded by the devices, the Appspace player software interprets and renders the app on the display screens based on the XML data.

Appspace currently provides HTML5-based player software that supports Chromebox devices, Flash-based player software that supports Cisco digital media player devices including the Edge 340 and DMP 4310, and a DirectX-based player software for PC-based video wall players.

The Appspace player software interprets the Signs XML document and renders the app visually. The Appspace player software contains basic components responsible for implementing content synchronization, scheduling logic, sign logic, and the visual presentation. All devices registered with Appspace also contain a software module called the Download Manager, which maintains content synchronization between the device and the Appspace server.


The below is a description of the components in device software responsible for content playback:

  • Download Manager:

    • Compares timestamps between the app on a device and the app on its registered Appspace instance. If the timestamp value returned by Appspace is equal to the value stored on the device, then the app is considered in-sync.

      The Download Manager idles and repeats the check at the next minute. If the timestamp value is different, the device is considered out-of-sync with the app on Appspace. The Download Manager then begins the Content Download process.

    • When the Download Manager determines that a device is out-of-sync, it begins the Content Download process by requesting a file listing from Appspace. The Download Manager compares the data, and identifies new files that need to be downloaded and old files that need to be removed.

      Once the content download is completed, the Download Manager validates the files against the file list to ensure there are no corruptions. Once all new files have been validated, the media player software is notified to display the new content. Concurrently, the Download Manager sends a “content in sync” status message to Appspace.

    • Reports content synchronization status and network status, and proof-of-play metrics.

  • Schedule Manager: Evaluates defined scheduling properties and determines correct content for playout based on schedule rules and device time.

  • Business Logic: Implements user-defined action scripting rules and conditions for the behavior of dynamic and interactive apps.

  • Presentation Manager: Renders the visuals of an app using technology-specific implementation of the player software.