Patent ID: 6998837

Claim:
A coupling unit adapted for providing at least one signal path between at least two of: a first device under test—DUT-, a first coupler, and a second coupler, wherein: each signal path is adapted to provide a unidirectional serial communication, the first coupler is adapted to be coupled to by a signal analyzer adapted to analyze signals received, the first coupler is adapted to receive signals from the coupling unit at one or more inputs and to provide signals to the coupling unit from one or more outputs, the second coupler is adapted to be coupled to by a second DUT, and the second coupler is adapted to receive signals from the coupling unit at an input and to provide signals to the coupling unit from an output, the coupling unit comprising a first and a second multiplexer, each adapted for selecting as its output one of its plural inputs, wherein: an output of the first DUT is coupled to a first input of the first multiplexer and to a first input of the first coupler, a first output of the first coupler is coupled to a second input of the first multiplexer, the output of the first multiplexer is coupled to the input of the second coupler, the output of the second coupler is coupled to a first input of the second multiplexer and to a second input of the first coupler, a second output of the first coupler is coupled to a second input of the second multiplexer, the output of the second multiplexer is coupled to an input of the first DUT.