From Wikipedia: MHEG-5 is a licence-free and public standard for interactive TV middleware that is used both to send and receive interactive TV signals. It allows a wide range of TV-centric interactive services to be deployed. It is used by Freeview and Freesat in the UK, Freeview in New Zealand, TVB in Hong Kong, Freeview in Australia, Saorview in Ireland and has been specified in South Africa.
Klaus served as Chairman of the ISO/IEC SC29WG12 group that developed and defined the standard for a few years, until the standard release 1997. Klaus was also the official representative of the German National Standardization Institute DIN.