What is the input format expected by the elog client for a required Datetime defined field when inserting a record? (Eg: October 26, 2016 = ? in the field's data parameter).

I have read some prior posts on this and the indication is that the input needs to use epoch time, however even when I enter 1477493161 or 0 the client still flags the variable data as missing. If this is in fact the format I shoud be using then I can provide a sample input and output message to illustrate my problem.