The switchboard connects the source and sink connections of the Keithley 6221 ( the + and - pins) to any two electrodes out of the 37 connections on the DSub.
The board is powered by a Lipo battery, and a charging circuit is included.
The control signals to set the switches come from either the Arduino in Dsub9, in which case they pass through the Isolators, or the Daisy Chain in Dsub9. These are selected by the jumpers labelled Daisy Chain ON/OFF
