There are basically only two types of transfer switches, possibly a second x2 on the list (I will get to that)
The Transfer switch I have if there is no power.. then it SHORE is connected, applying shore power to the RV does nothing (The switch is already in the proper position)
Starting the generator causes the switch to activate, after a time in period it connects the RV to the generator output.
I have seen one that uses two sets of contactors (or possibly 3), more on that in part 2)
When no power is present it is disconnected, Plug into shore and it pulls in one set,, Start the generator it pulls in a 2nd set..
The part 2 is that this type may also have a 3rd set for inverter power, But as I recall it did not.
However,, You can replace any t-way (Shore/Generator) switch with any other provided it will fit in the space provided,, Not need to get an exact same make/model they all do the same job, they all have the same connections.
Only thing you need worry about is the size (30/50) cause that's different, and in 30's you may have a difference if there are two air conditioenrs. (you can use the two A/C switch in any case you will just have some terminals not connected is all)
Home is where I park it!