SMS interrupt 0{ berita(0x0000,0x3fff); } show interrupt 1{ berita(0x4000,0x7fff); } Interrupt 0 and interrupt 1 call the same sub routine but for different purpose. When compiled, the C51 generated warning L15: MULTIPLE CALL TO SEGMENT Segment : ?PR?_BERITA?RTX Caller1 : ?PR?_SMS?RTX Caller2 : ?PR?_SHOW?RTX The program does'nt work at all if the HEX file programmed to the chip AT89S51. Any one please, How to omit the warning, or to use interrupts calls one sub routine for a different purposes. Thank you very much Kurnia Brahmana