My girlfriend has multiple remote controlled AC outlets in her room. In Dutch better known as Klik aan Klik uit (Click on Click off) or KaKu for short. They are not the real Klink aan Klik uit brand but a cheaper version of the Action (Dutch dump store). They all work at 433MHz to send the data to the outlets.
In a junk bin I found another KaKu (and a remote) and it would be nice to use it with the rest. But at first they didn’t seem to work with the original set. But after some testing I found out they could work together but only at address 0. Also on and off where reversed. But hey, it’s a start. Enough to open them up more to check the guts. And because new KaKu would replace a normal switch it was a wish to have a local switch/button to turn on/off the light as well.