Keithley dual multiplexer plug in card 37xx series keithley 3722 the keithley 3722 is a dual 1x48 multiplexer plug in card that offers two independent banks of 1x48 two pole multiplexers which is ideal for applications that require a high channel count the two banks can automatically be connected to the series 3700a mainframe backplane and optional dmm through the analogue backplane connection relays this connection allows the mainframe to reconfigure the card as a single 1x96 two pole mu