Keithley 7708 40 channel multiplexer module with automatic cjc screw terminals keithley 7708 p the keithley 7708 is a plug in module that offers 40 channels of 2 pole or 20 channels of 4 pole multiplexer switching it can be configured as two independent banks of multiplexers the built in cjc sensors automatically linearise thermocouples making the model 7708 ideal for rtd thermistor and thermocouple temperature applications it is also well suited for mixed signal measurement applicatio