The Model 2510 is a DC source with eight levels and three impedances that simulate Boonton sensors. The 2510 is used to calibrate all Boonton RF Power meters and RF Voltmeters such as the 4200, 4300, 4210, 42B/BD/C/CD, 9200/B, 92BD, and 92EA. These meters, although RF meters, require DC calibration of the "box” (main instrument) independently of the sensor so that all "boxes" are identical at the sensor output port, which is DC. This means that all boxes are interchangeable, without the requirement for AC calibration when swapped. The output of the 2510 is differential with a special Boonton connector that matches the Boonton power meter and voltmeter cable system. A special double shielded differential cable is used for interconnections. The 2510 is GPIB bus programmable with all functions available on the bus except the power switch. The 2510 is suitable for performance verification of Boonton meters (main instrument less sensor) , and for troubleshooting, by isolating the problem to the sensor or the main instrument.