ERROR CHECKING SYSTEM FOR TRANSMISSION CODE

摘要

PURPOSE:To attain a simple error checking system having high reliability by using the error checking codes BCC for 1-byte character block that is generally used in a computer and converting the code BCC coincident with a transmission control code into a proper 1-byte specific check code to avoid troubles. CONSTITUTION:A microcomputer (A) transfers the transmission characters to a buffer memory 6-2 from a transmission character memory 6-1 and sends them to a BCC calculation part 6-4 at every block. Here an exclusive OR is secured at every digit of characters for blocks for the production of a 1-byte BCC (T). Then a comparison processing part 6-6 compares the BCC (T) with all transmission control codes used. Then the BCC (T) if coincident with the transmission control code is turned into a specific check code and then sent to a data transmission part 7. The part 7 adds the transmission control codes STX and ETX to the front and back sides of a character block together with a BCC or a specific checking code put immediately after the ETX and transmits them to the remote side.