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

       /CSR_OFFSET=value

    For devices on multiple device boards, specifies the offset
    from the CSR address of the multiple device board to the CSR
    address for the specific device being connected. To specify the
    address in octal or hexadecimal, precede the address with %O or
    %X, respectively.