To speed up the cable project, Schwarz-Schilling decided to involve private companies in the cable laying. Sonnenschein KG also had its wife's company involved in the "Projektgesellschaft für Kabel-Kommunikation mbH", where he had been managing director for many years. His shares on the Sonnenschein KG, he resigned only a few hours before his appointment as Postminister. Buyer of these shares was the Nixdorf Group. His decision to use copper, met both at home and abroad to wonder: It was already foreseen in the early 1980s that fiber optic cables are the "technology of the future."