A german company that produced the Wiedmann BTX Modul for CPC or Joyce.
The company does still exist in 2010, and they do even still have Schneider and Amstrad logos on their webpage: http://www.wiedmann.com - however, they seem to be focusing on older (pre-computer) hardware now, see screenshots below.
Screenshots from www.wiedmann.com
- www.wiedmann.com as of March 2010
Homepage, 3/2010
Sonderposten, 3/2010
Eventmanagment, 3/2010
