Library /sys$common/syshlp/nclhelp.hlb create, modem_connect, line, rate select (OpenVMS)  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    The optional Rate Select argument specifies which of the
    line rates is to be used if none is specified when a call
    is set up.

    high    The value of the "speed" characteristic is used.
            This is the default.

    low     The value of the "alternate speed" characteristic
            is used.

    Example:

    create modem connect line DSY-0-0 -
         communication port DSY-0-0, -
         rate select low