Library /sys$common/syshlp/sysmanhelp.hlb IO, CONNECT, Qualifiers, /VECTOR  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /VECTOR=(vector-address,...)

    Specifies the interrupt vectors for the device or lowest vector.
    This is either a byte offset into the SCB of the interrupt vector
    for directly vectored interrupts or a byte offset into the ADP
    vector table for indirectly vectored interrupts. The values must
    be longword aligned. To specify the vector address in octal or
    hexadecimal, precede the address with %O or %X, respectively. The
    /VECTOR qualifier is required when you use the /ADAPTER=tr_number
    qualifier or the /NUM_VEC=vector-count qualifier. You can list up
    to 64 vectors.