A device where the equivalent resistance value of the device is controlled by digital signals. So instead of mechanical controlling the wiper position (e.g. turning a knob) you can do it using digital inputs. I suspect it internally uses simple digital logic circuits and a resistor ladder (similat to DACs) to implement it.

Check out Maxim's chips:

http://pdfserv.maxim-ic.com/arpdf/MAX...AX5161.pdf

kundi