Thanks Pixeleyes for the insights. However, I don't see that option under DTM "Edit Event Based Rule / Event Condition" field. Please elborate. Much appreciated.

Apparently, the option Pixeleyes mentioned is for Event serialization within SiteCatalyst reporting not DTM. Much appreciated if any insights within Adobe DTM rules setting for impression.

Based on business requirement and trying to figure out a way to fire beacon when enters the viewport for the first time only.The currently/available setting within DTM Impression "enter viewport" will record multiple time when user scroll up and down. Could anybody please help. Much appreciated for ...