What is the EPC Binary Header?

Per GS1's EPC Tag Data Standard (TDS), the general structure of an EPC Binary Encoding as used on a tag is as a string of  bits (i.e., a binary representation), consisting of a fixed length, 8 bit, header followed by a series of fields whose overall length, structure, and function are determined by the header value. 

The encoding schemes dare shown in Table 14-1 of TDS. That table also  indicates currently unassigned header values that are "Reserved for Future Use" (RFU).