Q - When adding an event, there are two choices for "Action Type" that I can't find an explanation for in any documentation:

COBOL Only
User Defined

See sample screen below:

Can we use them in any way?

A - "COBOL only" means it will call a COBOL program for you. If you are not a licensed Elliott COBOL developer, you still will need to find a developer (or ask Netcellent) to write this custom COBOL for you. Then you may ask, "What's the benefit of this event COBOL program approach over just simply modifying the Elliott COBOL programs?"  The main benefits are: (1) This would be a separate COBOL program that Netcellent will not modify, so if there's a new Elliott update and upgrade, it will not impact this custom COBOL program (unless there's a database-level change, which happens infrequently); (2) If you can implement the "custom action" through a COBOL program, then you can call this COBOL program through an event. You control the condition when the event gets triggered. The COBOL program carries out the action.  Overall, this is a more generic and flexible method over custom COBOL programming.

As for "User Defined," it means the event will write the triggering data to the SYEVTQUE table. Normally, our event handler will pick up the records in the SYEVTQUE table and process them accordingly (like sending e-mail). In this case, since it is user-defined, our event handling program does not do anything with it and simply skips it.  It is up to you to monitor the data in the SYEVTQUE table with an external program (like VB) and do what you need to do with it. Once your external custom program is done, it should delete the corresponding user-defined SYEVTQUE record.

The majority of our users use the "Email" option, a smaller portion of them use "Message Box," and a tiny portion of them use "Tickler." We are aware of one reseller that implemented the "User Defined"option. But we are not aware of anyone using the "COBOL only" option.  I hope this will give you a proper perspective if you are interested in spending more time investigating the "User Defined" or "COBOL only" options.