VMS Help SET, HOST, /DTE, Qualifiers, /DIAL  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /DIAL=(NUMBER:number[,MODEM_TYPE:modem-type])

    Allows a modem attached to the outgoing terminal line to be
    autodialed using the autodial protocol of that modem. The
    NUMBER keyword is the telephone number to be autodialed and is
    a required parameter.

    Before you dial a new number, you must log out of the current
    remote system.

    On Alpha, the MODEM_TYPE keyword defaults to DMCL (any modem that
    uses the DEC Modem Command Language).

    On VAX, the MODEM_TYPE keyword is optional. It can be used to
    specify any of the following modem types:

    o  DMCL (any modem that uses the DEC Modem Command Language)

    o  DF03 (default)

    o  DF112

    Each modem type requires a specific modem dialer code. Check with
    your system manager to see which modem dialer codes are installed
    on your system.

    In addition, the MODEM_TYPE keyword can be used to specify
    a modem type other than DF03, DF112, or DMCL. A template is
    provided for users interested in supporting other modems with
    autodial capabilities (see SYS$EXAMPLES:DTE_DF03.MAR).