...that's it....I've read a lot of posts here, read the docs, but sending a simple "1" or "0" is about as clear as mud. Bear in mind, my programming skills are rusty at best.I don't expect anyone to write my code for me. However, like anything in life, some things are difficult if not impossible until you know how to do it.I know that I have to use "TransmitClientEvent", but what about all that other stuff to make this one line function properly?Ray

At FSDeveloper.com, Simconnect forum, you can find several projects in C#. See if that can help you.Jos

I'm finishing up my first project for FSX, but after I release that, I'll wrap up my C# tutorial for SimConnect.

Well, here's how I did the Avionics master in c if it helps at all.SimConnect_MapClientEventToSimEvent(hSimConnect, KEY_EVENT_AVIONICS_TOGGLE, "TOGGLE_AVIONICS_MASTER"); SimConnect_TransmitClientEvent(hSimConnect, 0, KEY_EVENT_AVIONICS_TOGGLE, 0,SIMCONNECT_GROUP_PRIORITY_STANDARD, SIMCONNECT_EVENT_FLAG_GROUPID_IS_PRIORITY); -------------------------------------------I'm sure someone will correct me if I'm wrong. But unless otherwise specified, you will use a 0 for a toggle switch. The dme select says to use (1,2), thusSimConnect_MapClientEventToSimEvent(hSimConnect, EVENT_DME_SELECT, "DME_SELECT");SimConnect_TransmitClientEvent(hSimConnect, 0, EVENT_DME_SELECT, 1,SIMCONNECT_GROUP_PRIORITY_STANDARD, SIMCONNECT_EVENT_FLAG_GROUPID_IS_PRIORITY);andSimConnect_TransmitClientEvent(hSimConnect, 0, EVENT_DME_SELECT, 2,SIMCONNECT_GROUP_PRIORITY_STANDARD, SIMCONNECT_EVENT_FLAG_GROUPID_IS_PRIORITY);Hope this helps a little.