To improve testability of analog or mixed analog/digital circuit modules mounted on a carrier, three-way switches are placed at input and output ports of the circuit modules. The switches can operate to establish signal connections between a test bus and core circuits inside the modules. The switches...http://www.google.de/patents/US5581176?utm_source=gb-gplus-sharePatent US5581176 - Analog autonomous test bus framework for testing integrated circuits on a printed circuit board
