Hi, I'm trying to add the intercom to an older version of entryphone the v200 but they only have wiring diagrams for a v201, i have slightly different labels on the board  A1 is the power, i can see that on the board A2 is port L which i believe that's for the ringer, but in my device port L is for speech A3 is to port p, which i believe is audio output/ microphone A5 goes to port 1, which i believe is open door, on mine that's called button but sounds right A6 to port A1 ringer activator but in my system a1 isn't used but b1 is, possibly because that's linked to other flats. Any thoughts on if i would likely be OK just wiring in as per the instructions?