The MAX232 generates its own RS232 voltage levels from a +5V input. It has two drivers and two receivers on one chip, the receivers are good to +/- 30V. -- View this message in context: http://elecraft.365791.n2.nabble.com/Bluetooth-and-Elecraft-Rig-Serial-Comms-tp7572526p7572546.html Sent from the Elecraft mailing list archive at Nabble.com.