#define PART_A \
    U8    SDser[8]  ; /* serial number */\
    U8    SDaddr    ; /* address assigned to sign */\
    U8    SDdips    ; /* dipswitch setting */\
    U8    SDtype    ; /* type of sign */\
    U8    SDwidt    ; /* width */\
    U8    SDhgth      /* height */

struct DUMMY_STRUCT
{
    PART_A;
};

typedef struct h
{
    PART_A;
    // fill struct h to be 256 long
    U8    SDfill[255-sizeof(struct DUMMY_STRUCT)] ;  
    // put this one last
    // here store error number if FRAM match/update failed.
    U8    SDerno    ; 
} SIGN_DESC;