Max doesn't seems to be playing well with an Arduino Duemilanove. I loaded the example program onto the Arduino with Arduino 0013 programming environment. I open the Serial Communication tutorial. The correct serial port and baud rate is in the serial object. I activate the metro and send a byte. I see the RX light up on the Arduino but no data flow through the patch. I send 10 to the Arduino in the Arduino 0013 programming environment and the program runs fine using the Serial Reader in that program.