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

       /VECTOR=vector-addr

    Specifies the UNIBUS address of the interrupt vector for the
    device or the lowest vector, if more than one exists. This
    qualifier must be specified for UNIBUS devices. For devices on
    multiple device boards (for example, the DMF32), the address must
    be the interrupt vector address for the multiple device board
    specified in the output of the CONFIGURE command. To specify the
    address in octal or hexadecimal, precede the address with %O or
    %X, respectively.