Echo Mode
RP1210A VDA vendors have implemented Echo Mode differently in the past (which affects the "Echo Byte" on received messages). Some vendors thought that "any" message sent should be treated as a "generic message appearing on the datalink" and therefore should be returned during a call to RP1210_ReadMes-sage ( ). Other vendors only returned a sent message when Echo Mode was turned on (ensuring the message had an ECHO byte of '1'). Since the majority of vendors only return the sent message when Echo Mode=1, any RP 1210- compliant API will only return a message sent by RP1210_SendMessage () to the application when Echo Mode is on and will include the echo byte in the message set to '1'. If an application turns Echo Mode on, all messages that are echoed back to the application will pass through all filters that have been set. Therefore, if an application is interested in reading its own messages, it can turn Echo Mode to the "on" position and ensures the correct filters for it are set.