Basic door intercom wiring

[ivandrago]

I need some help with wiring a 2 handset intercom (Bell 902).

I've got a cat5e from each handset to the outside speech unit and a further cat5e from the power supply to the speech unit.

So I am connecting green to T, blue to O, orange to R and brown to I at the handsets and then to the correspondng letters at the speech unit.

What I am confused about is H and C. I have a cat 5e from the power supply so I need only 1 core for each. Assuming I use white-brown for H and white-blue for C, how do I then connect the white blue for C into the bottom of I for each handset at the speech unit?

This is the wiring diagram:

 

[ivandrago]

From the diagram it looks like I need to connect 2 cores from the 12V AC power supply to H and C?

 

[ivandrago]

ok, so use two cores and wire it where it tells you. Wiring diagrams are really easy to follow. You don't need to over think it

I get that part lol.

The part I am not sure about C to 1 and C to 2. Is that a single core from c to 1 and then from 1 to 2?

 

[ivandrago]

So I connected it up as follows with 1 handset (there are 2) but all that happens that the breaker trips:

 

[ivandrago]

Update: my wiring was all correct and it works fine. Turns out that the the MCB the Electrician told me it's on was incorrect