You can exchange the so-called “document types” FTAM-1 (for text files) and FTAM-3 (for binary files) with FTAM partners. This function is not available on z/OS.
The file structure and contents of these FTAM files are described in the Kernel group in “contents-type”:
constraint set
The constraint set describes the file structure. The subset of the FTAM standard selected by the functional standard ISO/EN 10607-3 permits only the value unstructured.The constraint set also specifies the actions which are permissible with the file on the basis of the structure of the file. For unstructured files, read, overwrite, extend and delete operations are permitted. Together with the permitted actions, the constraint set restricts the set of possible actions on a file.document type
describes the actual contents of the file. ISO/EN 10607-3 requires support of FTAM-1 (unstructured text) and FTAM-3 (unstructured binary) for files with binary contents. The string format (string significance) can be variable (variable), fixed (fix) or not significant for storage (not significant). Furthermore, a maximum length of the string (maximum string length) can also be defined.In the case of text files (FTAM-1), the universal class number specifies the characters present in the text:
GraphicString can contain all graphical character sets (G sets) and escape sequences can be used to switch between character sets (see ISO 2022).
openFT sets the character set to ISO 646 IRV (or ASCII IRV or ISO 8859-1 G0 set) plus ISO 8859-1 G1 set which broadly covers the characters used in the European languages. When two partners interconnect with openFT as of V10, the character set for file transfer is set to UTF-8.
GeneralString may contain not only graphical characters but also controlcharacter sets (C sets) which can also be switched.
VisibleString contains only graphical characters from ISO 646 IRV.
IA5String contains graphical characters from ISO 646 IRV and control characters from ISO 646 (C0 set).