A few weeks ago I received unique pictures of the Ericofon, showing the heart of the phone.
Copyright: Thomas Becker, Hochschule der Künste Bern (HKB), Konservierung und Restaurierung (KuR), Switzerland
Thank you Thomas!!
If you look at the right picture above and the last picture in the Sewn Open post, you can see that the bar is obviously a ‘standard’ that occurs more often in flat earpieces. But still no clue why…