Home intercom system: low voltage?

[Stan Calow]

Is anyone familiar with how home intercom systems (25 yrs old) are normally wired? I was assuming they are normally low-voltage but dont know if that's true (its not functioning so can't test). I am looking to install a Ring doorbell system at a friends house, and can't tell if the existing intercom system is wired into a low-voltage transformer somewhere in the system. Very messy installation so hard to trace wiring. Thanks for any input.

[Arthur Fleming]

I’m an electrician in Massachusetts, been licensed since 1984, and I’ve never seen an intercom system that wasn’t low voltage. Somewhere’s there’s a transformer, or was a transformer. This a single family house?

[Shawn Pixley]

It should be low voltage. Somewhere there is a transformer driving (or not) the intercom system. Ours was a wall wart in a closet.

[Stan Calow]

Thanks guys that helps. Yes its a single family house. I'll look for a transformer somewhere in the house. That should be easy to replace. I did do a google search to answer the basic question, but could not get past all the ads to solid information.

[Steve Peterson]

The one in our house is low voltage. Built in 2000 or 2001, but the design looks like it is from the 1970's. Each wall unit runs wires to the control box below the house that is about 4" by 6" by 2". The control box uses a wall wart transformer.

[Stan Calow]

Thanks Steve, that sounds like what we have. We will be hunting for the transformer in the basement.