Patent ID: 6963196

Claim:
An output termination auto detection circuit for an input device having an output terminal coupled to an input of a host instrument having discrete input resistance terminations wherein the output termination of the input device is the input termination of the host instrument comprising: a reference resistance in the input device selectively coupled to the output terminal of the input device; a signal source disposed in the input device coupled to the one side of the reference resistance; a detection device disposed in the input device coupled to the other side of the reference resistance at a common node between the reference resistance and the input termination resistance of the host instrument for generating a digital value representative of a voltage at the common node; means for determining the output termination of the input device as a function of at least two digital values representative of the voltage at the common node, the reference resistance and the voltage of the signal source, and generating an output when the output termination of the input device is improperly terminated; and a display element coupled to receive the output of the determining means for indicating an improper output termination of the input device.