The FC-4 Features associated with FC-4 Types on this port encoded as a 128-byte value in network-byte order, or the zero-length string if no 'FC-4 Features' have been registered.

Section 5.2.3.15 of FC-GS-4 is the authoritative definition of the format of the 128-byte value, i.e., if different, FC-GS-4 takes precedence over the following description:

The 128-byte value is an array of 4-bit values, one for each FC-4 Type value, positioned as follows: the 5 most significant bits of a Type value identify where it appears within the 128-byte value, specifically, within which word:

- Word 0 (of the 128-byte value) contains information related to Types '00' through '07'; - Word 1 contains information related to Types '08' through 0F'; - and so forth, up to Word 31, which contains information related to Types 'F8' through 'FF'.

The least significant of the eight 4-bit values in each Word represents an FC-4 Type with 000 as its 3 least significant bits, and most significant 4-bit value in each Word represents an FC-4 Type with 111 as its 3 least significant bits.