Cell Master User Guide : General Information : Calibration and Verification
 
Calibration and Verification
Anritsu recommends annual calibration and performance verification by local Anritsu service centers. The Cable and Antenna Analyzer mode requires calibration standards for OPEN, SHORT, and LOAD (OSL) or InstaCal module, which are sold separately.
Note 
Anritsu recommends allowing the instrument to warm up to typical operation temperature (approximately 15 minutes) before calibrating.
The Cell Master is self-calibrating and there are no field-adjustable components. The OSL calibration components are crucial to the integrity of the calibration. As a result, they must be verified periodically to ensure performance conformity. This is especially important if the OSL calibration components have been accidentally dropped or over-torqued.
Contact information for Anritsu Service Centers is available at: www.anritsu.com/contact-us.