Use the switch macro for M1: "SWT21;" (without the quotes) ----- 73, Stan - KR7C -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-Is-there-a-serial-port-command-for-send-message-M1-tp7590195p7590196.html Sent from the Elecraft mailing list archive at Nabble.com.