I think I came to the right place to ask this question.
I have an 20 years old Siemens intercom and it didn't speak anymore to the person outside ringing the doorbell. There are 2 'phones' in the house. And both didn't transmit my voice to de outdoor speaker anymore so I'm positive this speaker is dead. Also I did a small test to take a small telephone horn speaker an attached it to the outdoor intercom and then connect it briefly to the intercom doorbell outside. Then I did hear the person speaking inside.
I took the 50mm radius speaker out and looked at the specs of it on the back of the magnet. Quite special specs and these days I'm not able to find anything like it online to replace it with. It reads: (brand is unclear to me)Buk(son?) 50RF04N 65Ω0.3W KOREA
Can anyone help me out on suggesting a replacement speaker for this exotic one?