The Networked Variable feature in BrightAuthor requires an .xml file to update. The .xml file uses a simple RSS <item> tag. The <title> tag contains the variable name, and the <description> tag contains the variable value:
<?xml version="1.0" encoding="utf-8"?>
<rss version="2.0">
<channel>
<item>
<title>test</title>
<description>50</description>
</item>
</channel>
</rss>
In the example below, under File > Presentation Properties > Variables, the variable is pointing to an .xml file in a Dropbox account. When you select Validate, BrightAuthor attempts to read the value in the description field of the .xml tag.
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BSN Live Data Feeds
If you have a BrightSign Network subscription, you can use the Live Data Feed feature to update Networked Variables. With Live Data Feeds, each Title field specifies a variable name, and the corresponding Value field specifies the value of the variable.