How to connect a computer to the intercom line?

Question

Electronics

How to match audio input and output to a two-wire line?

Simplified diagram of devices on both sides:

Answer 1

If you do not want the magic smoke on which it works to come out of the computer, connect it through two isolation transformers.
By the way, there should also be a button.

Answer 2

If you have an intercom with an analog signal, and there is a simplified circuit such that you drew, then this is very strange. There should be an "anti-local circuit" on the transformer, you need to get the same one, connect it to the line and see the output level (preferably with an oscilloscope). With a divider, adjust this level within 1 V and bring it to the sound card as a linear signal. Trans can be obtained from an old phone with MB, if you find one, of course, or from the subscriber terminal of such an intercom (more reliable)