The Model 7064 is a 20 channel low-voltage scanner card. The card is designed to introduce a minimum of voltage offset error (less than 1/xV differential thermal offset from input to output with copper leads) for sensitive tests such as low-level transducer and thermocouple output switching. Channel switching allows one signal to be switched to as many as 20 channels or 20 channels to one channel. In the latter configuration the channels are switched one at a time. The Model 7064 works in conjunction with an appropriate scanner mainframe such as the Keithley Model 705 or Model 706. The card is configured as desired then plugged into the mainframe. The mainframe controls channel switching using either the front panel controls or commands over the IEEE-488 bus. With multiple Model 7064 cards and several Model 706 mainframes daisy chained together, up to 1000 channels can be switched. High channel isolation, 10¹²Ω, minimizes cross channel interference and noise. Expected relay life, greater than 1,000,000 closures, is obtained when signals less than 10V or 10mA are switched (non-inductive load only). However, peak signals up to 40V or 100mA can be switched. Quick disconnect screw terminals facilitate input and output connections to the scanner card.