A similar trackball device at the German ' was constructed by a team around of Telefunken as part of the development for the Telefunken computer infrastructure around the main frame , process computer TR 86 and video terminal SIG 100-86, which began in 1965. This trackball was called ' (German for "rolling ball"). Somewhat later, the idea of "reversing" this device led to the introduction of the first computer ball mouse (still named "", model RKS 100-86), which was offered as an alternative input device to light pens and trackballs for Telefunken's computer systems since 1968.