Hi When i type this, struct cmd_pkt{ int type; int OGF; int OCF; int len; unsigned int far data_pkt[256]; }; struct cmd_pkt c_pkt; After I complied it, it prompt me with this error. Error 172: '?DT?BT_COMMAND': segment too bigt (act = 526, max = 128) The maximum value that I can put before getting this error is 40. What causes this error? Can this error be overcome? When I tried this(meaning without the structure), unsigned int far data_pkt[256] it did not give me any error. Why? I'm using the MCBx51 V2.1 Prototype Board with the 80251 chip.. Thanks in advance.