Abstract: An apparatus for a test system for testing an electronic circuit. The apparatus includes an interconnect path, a comparator, a programmable apparatus, a first Schottky diode, and a second Schottky diode. The interconnect path has a first end and a second end. The first end of the interconnect path is coupled to the electronic circuit under test. The interconnect path transmits a signal from the electronic circuit under test to the second end of the interconnect path. The comparator is coupled to the second end of the interconnect path for receiving and comparing the signal from the electronic circuit under test with a reference voltage. The comparator has a high input impedance. The comparator provides an output signal to the test system. The programmable apparatus provides a selectable first voltage and a selectable second voltage. A first Schottky diode is provided for reducing ringing of the signal from the electronic circuit under test.