A system and method for synchronizing otherwise independent oscillators private to I2C Bus slave devices. An I2C Bus master device is capable of issuing two new general call commands, MEASURE PULSE and RESET PRESCALE. The I2C Bus slave devices respond to the MEASURE PULSE command by returning a digital count related to the number of ticks its local, private oscillator cycles through during a signal pulse on the I2C Bus. All such I2C Bus slave devices measure the same signal pulse on the I2C Bus, so the differences in the digital measurements returned during the MEASURE PULSE command are proportional to their respective oscillator frequencies. The various digital measurements returned are used to calculate appropriate oscillator prescale factors that will harmonize the final product frequencies of all of the local oscillators on all of the I2C Bus slave devices in the system.