Library /sys$common/syshlp/pca$help.hlb DEFINE, /KEY, Description  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    The DEFINE/KEY command assigns PCA command strings to keypad
    keys. When you press the appropriate keypad key, PCA enters the
    associated command string into your command line.

    The key definition remains in effect until you redefine the
    key (by issuing another DEFINE/KEY command for the same KEY),
    issue the DELETE/KEY command for that key, or exit. You can
    include key definitions in a command procedure, such as your
    PCA initialization file.