Hi, we have a BPT YC-300 (System 300 X1(2 Wire) intercom in our flat. I bought a Bell 801S (with on/off privacy function to be able to switch the intercom off if we don't want to be disturbed at certain times...I work nights...) I did this before in our previous place, but was shocked to find that the BPT's wiring is totally different to the Bell's. I only have an orange and orange/white cable used in the BPT both connected to "B". I tried connecting them to the IROTZ points in Bell but couldn't make it work. Long story short can anyone recommend an intercom with privacy or on/off function to replace the BPT YC-300 unit which doesn't have this option. Many thanks