Differential Quad 1x40 Multiplexer Card The Keithley 7002-HD-MUX1 is a Differential Quad 1x40 Multiplexing Card and has four 1x40 (twopole) multiplexers, providing a total of 160 multiplexer channels per card. In addition, a unique 4x4 instrument connection matrix supports reconfigurable instrument connections. This instrument connection matrix connects to each of the four 1x40 multiplexer banks, allowing the card to be programmed as a quad 1x40, dual 1x80, a single 1x160, or a 4x160 blocking matrix. In addition, each bank of multiplexers can be linked through a software configurable backplane relay, allowing even more configuration flexibility.