I have a remote flip-flop on the stick, but it?s connected to the GPS/Comm instead of the SL30. However, the SL30 does have a remote flip-flop input and allows you to toggle the comm frequencies when they are displayed or the nav frequencies when they are displayed. Sorry, I can?t help you out on the SL40.
To piggy-back on your thread I have another question regarding the remote flip-flop feature. If you have two radios with this capability and are using them through an audio panel (GNC 300XL/SL30/PS7000 in my case, but any combination of equipment would apply), is it possible to use the remote flip-flop on the radio that is selected as the transmitting radio? For example, when transmitting on Nav2 the remote switch will toggle the frequencies on the second radio instead of the first. On our first long x/c I thought that feature would have been nice.