The Datron Models 4800, 4805 and 4808 are high-precision Multifunction Calibrators which feature exceptionally high stability and full systems capability. They are characterized by wide-range coverage of DC Voltage, AC Voltage, DC Current, AC Current and Resistance functions in a single unit. The 4800 and 4808 calibrators consist of a mainframe to which various output options may be added. The 4808 has a higher specification them the 4800 and has an additional AC Voltage 'Spot Frequency' calibration facility. The 4805 is a fixed configuration instrument containing all the above functions as standard. All three calibrators incorporate a reference module which maintains a high accuracy specification over the ambient temperature range of 23°C ± 10°C. A high level of stability is achieved by the use of specially selected and tested reference components and ultra-stable gain-defining resistors. The calibrators' ‘Autocal feature ensures that their 24~hour specifications are usable - not merely figures of merit - and all three models feature a 'Shadow Calibration' facility which allows new calibration data to be stored, but not implemented, until the integrity of the metrology standards used in the unit's calibration has been verified. The 4800,4805 and 4808 ail feature microprocessor control for instrument management, simplifying their use during complex manual operations such as die calibration of high-quality digital multimeters. Their IEEE 488 interface provides a comprehensive remote programming capability, allowing fully automated instrument control, and programmed calibration of the calibrators themselves.