Door intercom systems, intercom systems, doorbell - experiences

Hello everyone,

I am considering which door intercom system to choose,

Does anyone have experience with products from SKS, TCS, or Mathfel?

I would preferably like to have a camera in the doorbell and a display inside; if this is too expensive (no more than 500€), I would also be happy with just an indoor station with intercom and door opener.

The intercom or doorbell indoor unit should be installed once on the ground floor and in the basement.

Furthermore, how does such wiring look? Does one line run from my distribution cabinet in the basement to the outdoor station and to the respective indoor station, or is the supply line looped from indoor unit to indoor unit and then on to the outdoor station?

Thank you again for your answers.

Best regards, Gerd

Our intercom system is from Siedle and almost 40 years old. Of course, without a camera.