The 40-617 18-Bank, 3-Channel, 1-Pole Multiplexer Module forms part of the System 40 PXI Programmable Switching system. The Module consists of 18 electrically isolated banks of multiplexers controlled by a PXI/PCI interface. Each bank is a 1 to 3 multiplexer and operates with break-before-make action when a new channel is selected. Any Individual multiplexer bank can have a channel set by itself, alternatively, multiple banks can have channels selected simultaneously. Inter-bank linking relays allow multiplexer size to be increased in multiples of 3 by joining the common terminals of adjacent banks. Closing one linking switch produces a 6 channel multiplexer, closing all linking switches produces an 54 channel multiplexer.