The 54300A Probe Multiplexer is a programmable, dual eight-to-one probe multiplexer designed to expand the input capability of instrumentation with 50-ohm inputs. The unique strength of this multiplexer is its configurability. The user may select from three different input pods (sold separately): two high-frequency, high-impedance probes, or a 50-ohm BNC input for terminated line applications. The 54003A is ideal for delicate situations where high-frequency connections must be maintained and probes cannot be conveniently moved from one connection to another. Complex measurements can be automated by using the multiplexer's 16 inputs, switching one or two of them at a time into the test instrument, under computer control. In situations requiring more than 16 inputs, multiplexers may be cascaded in series to give a total of 128 inputs. Features full HP-IB programmability as well as simple front-panel control. It also has non-volatile memory for storing lists of switching steps. Switch lists can be advanced step-by-step from a front-panel button, over the HP-IB or for data logging applications, through a TTL pulse entered at the rear panel.