The PM 8820 and PM 8821 universal, compact 8 bit logic Pods comprising 8 identical level detectors (contained in 4 high speed dual differential comparators/sense amps.) with a common wide range threshold, high input impedance and TTL compatible outputs. Power is derived from the unit the logic probe is being used with. Both Pods the PM 8820 and PM 8821 are identical in contruction, with the exception of the ribbon cables and connections. The PM 8820 has a 20 wav ribbon cable and connector, the PM 8821 has a 1 6-way cable and connector.