Library /sys$common/syshlp/nclhelp.hlb create, x25_protocol, dte, pvc, window_size  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Window size for the PVC. This argument determines the value of
    the window size characteristic. This value should be within the
    maximum and minimum window size specifier by the parent DTE.