Event-Driven Data Layer (EDDL): A general term referring to any data layer that is designed to respond to data that is pushed into it, where each push is termed an "event". There's a good write-up about this at https://jimalytics.com/tag-management/the-event-driven-data-layer/. Google Tag Manager's dataLayer is a common implementation of a EDDL.
Direct Call Rule (DCR): This is a feature that is specific to Adobe Launch (or what is now called Adobe Experience Platform Data Collection Tags). By running _satellite.track("identifier") anywhere in a web page, you can trigger a Rule in Adobe Launch that listens for that Direct Call event with the "identifier" value. You can read more about how to use it at https://experienceleague.adobe.com/docs/experience-platform/tags/extensions/adobe/core/overview.html....
Hope that helps!
Direct Call Rules are something used within Adobe Launch, the tag management system.
A direct call event bypasses event detection and lookup systems. Direct call rules are ideal for situations where you want to tell the system exactly what is happening. Also, they are ideal when the system cannot detect an event in the DOM.
When defining a direct call event, you must specify a string that will act as this event’s identifier. If a trigger direct call action containing the same identifier is fired, then any direct call event rules listening for that identifier will run.
CEDDL & EDDL are both data layers.
A good way to remember the difference is the CEDDL is 25% more difficult to spell and to implement.
The Event-Driven Data Layer describes what you’re implementing: a data layer that is constructed and transmitted to your TMS by events.
ACDL - Adobe Client Data Layer is Adobe's event driven data layer built on Adobe Experience Manager(AEM)