question: private boolean checkFirstByte ( byte first ) { return ( first == ( byte ) 0x02 ) || ( first == ( byte ) 0x81 ) || ( first == ( byte ) 0x01 ) || ( first == ( byte ) 0xC1 ) || ( first == ( byte ) 0x03 ) || ( first == ( byte ) 0x13 ) ; }
target:  This function checks that the first byte of the received message is correct.