OBD (ISO) to RS232 Interpreter（ELM323）.pdf

ELM323 OBD (ISO) to RS232 Interpreter Description Features Since the 1996 model year, North American • Low power CMOS design automobiles have been required to provide an OBD • Crystal controlled for accuracy (On Board Diagnostics) data port for the connection of test equipment. This port is used to obtain • ISO 9141-2 and ISO 14230-4 protocols emissions-related diagnostics information, and in • Configurable with AT commands some cases can also be used to obtain real-time vehicle operating parameters. • Standard ASCII character output The ELM323 is a 14 pin integrated circuit that, • Four high current LED drive outputs with only a few external components, is able to convert between the OBD data format and the standard RS232 serial data format. This allows virtually any personal computer or PDA to Connection Diagram communicate with a vehicle using only a standard PDIP and SOIC serial port and a terminal program. If desired, (top view) hobbyists can even create their own custom ‘scan tool’ by adding an interface program. Please note that while this integrated circuit has VDD 1