The current Secure Shell protocol and current clients do not transfer any information about the files to be transferred, only the file contents as a byte stream. This is sufficient for Unix-type files if the sender and receiver use the same coded character set (CCS).
Tectia Server for IBM z/OS needs more information: which transfer format to use, what
coded character sets are involved, and what the file characteristics
are. When Tectia is used at both ends, the information can be relayed
by using the Site commands of
read from environment variables. When a third-party Secure Shell client
is used together with Tectia Server for IBM z/OS, the information can be either encoded
in the filename (advice string), read from a file transfer profile,
or read from environment variables.
For more information, see Tectia Server for IBM z/OS User Manual