Library /sys$common/syshlp/latcp$help.hlb SET, PORT, Qualifiers, /PORT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /PORT=remote-port-name

    Specifies the name of the remote port on a terminal server that
    supports a remote device, or specifies the name of a remote port
    dedicated to an application service on a remote LAT service node.
    In either case, the remote port is logically associated with the
    specified application port on your local node.