VMS Help TCPIP Services, TELNET, TN3270 Keyboard Functions, SELECT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    VT100: EXT + K              VT200: Select
    DEFINE_KEY Function: SELECT

    Lets you choose items from a menu, table, or list and then notify
    the program of your selection. Use the arrow keys to position
    the cursor on the field designator character, then use the SELECT
    function. For more information on using SELECT, refer to the
    user's guide of the remote application.