This particular set is perhaps the most economical branded intercom set on the market. It consists of 2 cables (1+N), an aluminum main unit, and plastic internal earphones. I recommend purchasing and installing an additional transformer for door unlocking (cost 10€) because things seem to be borderline with the one included in the set. The operation is as follows: the bell rings (3 volume levels to choose from), we press the communication button once and it remains open for several seconds, and finally we press it again to close the communication and click the unlock button.

It doesn't work well. It is digital, so when you press the button, you have to wait a little while for the other person to hear you. Also, after the door closes, the sound continues to be transmitted and if you speak inside the house, they can hear you from outside. This lasts sometimes up to 2-3 minutes.