The Model 8032 Multiplexer expands the number of channels that can be read by the Model 8600-1/2 Dataloggers or the Model GK-404 Vibrating Wire Readout. The channels are protected against voltage surges with tripolar plasma surge arrestors and bipolar surge arrestors. Optional manual switches may be connected to the terminal board that permit easy access to each channel of the multiplexer for taking manual measurements with a portable readout in tandem with those taken automatically with the datalogger.