The PulseNET Summary view displays three columns that indicate different device status.  Below is an explanation of each.

The Status column shows the current alert status for the device meaning it will indicate any outstanding, un-cleared alerts. The icon will correlate to the most severe status. The device can show available but still have outstanding alerts that have not cleared.

The Availability column is a graphic image indicating the trend of the availability over the current reporting period (default is 4 hours). To view the actual data points over the time period, hover over the image or click the image.

The Health column indicates the health history of the device. By hovering or clicking on the icon, the history is displayed in graphical form during the time range currently being viewed (default is 4 hours).