The SRS 121.3 three-phase electronic system reference standard has been especially developed for use with meter test systems. The SRS 121.3 electronic system reference standard is a precision measurement unit for all AC values that are used in the measurement of energy.
 
Its wide measurement range, high precision and excellent immunity to interference are the outstanding features of this instrument. It is the ideal measurement unit for verification of electricity meters in the test area. This reference standard is operated completely via the RS 232C serial line interface.