An interconnection system for an electronic biological waveform simulator device utilized for testing the operability of a biological waveform sensing machine such as a vectorcardiogram machine. The system includes a housing with a major surface and a circuit board within the housing containing electrical circuitry for generating output signals simulating a biological waveform. A plate affixed to the major surface of the housing includes an undercut slot adapted to receive a disc-shaped electrode commonly used with the sensing machine. A connector disposed in the slot electrically connects the electrode, when engaged in the slot, with the circuitry. Preferably, the system includes a second connector projecting from an upper surface of the plate for receiving jacks utilized with disposable electrodes. In the preferred embodiment, the first and second connectors are electrically connected together so as to provide alternate signal paths for the simulated waveform from the electrical circuitry.