Nuclear explosion monitoring capability is fundamentally dependent on monitoring station installation. These stations are being installed during the preparatory phase prior to entry-into-force of the Comprehensive Nuclear-Test-Ban Treaty and they will provide essential detection capability. However, once installed, their full potential, particularly location capability, will not be realized unless calibrated. Calibration is not required by the treaty, but rather is a voluntary activity allowed under the Confidence-Building Measures part of the treaty. There are many aspects of calibration as evidenced by the several terms of the descriptive equation; furthermore the importance of calibration to each term is different for each monitoring technology and will be implemented to some degree for all technologies as part of normal installation and operations. This paper focuses on seismic calibration because of the significant role outside of operations that can be played by the global research community in conjunction with their representatives to the PrepCom.