/sys$common/syshlp/helplib.hlb SET, HOST, /LAT, Qualifiers, /AUTOPROMPT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /AUTOPROMPT (default)
       /NOAUTOPROMPT

    Causes an OpenVMS Username: prompt to appear with no user action
    when a SET HOST/LAT command is issued.

    On a terminal server port, you can configure the port to have
    AUTOPROMPT disabled (/NOAUTOPROMPT) so that you are required
    to press Return when connecting to a node to get the Username:
    prompt; however, when connecting to a reverse LAT service, the
    AUTOPROMPT characteristic should be disabled.