Replacing Entry phone Bitron AN0002 with Fermax 3431 Universal Handset

22 Sep 2021
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United Kingdom
Seeking assistance on replacing a Bitron AN0002 with a Fermax 3431 which I thought would be a straight swap, but having a difficulty and hoping someone can help.

The Bitron AN0002 has 6 wires

C7 – no wire

11 - 2 wires (green with white, white with green)

1 - 1 wire (blue with white)

2 - 1 wire (white with blue)

9 – 1 wire (white with orange

6 -1 wire (orange with white)

Instructions with the Fermax state that

Fermax = Bitron
1 = 9

2 = 2

3 = 6

6 = 1

4 = 11

So wired as above with the 2 slide switches on Z (Buzzer Call) and U- (Common Ground)

Everything seems to work apart from the Buzzer. Terminal no. 11 has 2 wires going into it and so just did the same when putting these into terminal no. 4 on the Fermax. Not sure if this was the correct thing to do. I assumed it would work given it’s a universal replacement and the model is stated on the instruction. Appreciate your help.

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From reading the manuals, I believe your wiring is correct, however the two wires going into 4 seems ....interesting!
Does the entry system also connect to other flats?
It might be worth having a peak under the call button plate to see how that green/white pair of wires are terminated.
Good luck!
Last edited:
Thank you for the reply. There are 18 flats in all and as far as I know everyones entry phone is working fine. Mine is Flat 3 and I know Flat 1 buzzer works as I have tried/heard it. Not tried any others. Still not resolved as not opened the main panel at the block entrance for fear of not being able to put it back again. May have to call in an expert. Haven't ruled out it could be the new unit, but unsure how to test the buzzer as everything else works
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Just old, discoloured and dated look. Nothing done to resolve issue so far

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