I would like to configure my serial communication to have no parity, 1 start- and 2 stop-bits. The documentation for Serial.begin(speed, config) states: (...) An optional second argument configures the data, parity, and stop bits. The default is 8 data bits, no parity, one stop bit. The documentation also lists the possible configuration-values. According to my (limited) understanding, I need SERIAL_7N2 or SERIAL_8N2 to meet my requirements. (I'm not sure how the data-bits relate to the the 1-start-bit that I need.) However, I can't even compile because I have no idea how to supply that config value to the begin method. (I don't have much Arduino/C++ experience) I've tried in my code the following two variants: Serial.begin(9600, SERIAL_8N2); Serial.begin(9600, "SERIAL_8N2"); Am I missing something? Additional Information: Serial.begin(speed, config) has been introduced with the latest Arduino 1.0.2 IDE version. The code defining/implementing the begin methods can be found here. HardwareSerial.h HardwareSerial.cpp Edit: According to the replies from PeterJ and borges, the following variant is correct. Serial.begin(9600, SERIAL_8N2); However, it's still not working. I found that the compile error doesn't occur if I change the configured board from my Arduino Leonardo to Arduino uno. Therefore, it could be a bug occurring only with a subset of boards ... or maybe it's not supported?!