Sch 1H para 22
The taximeter shall be equipped with a real-time clock by means of which the time of the day and the date are kept, one or both can be used for automatic change of tariffs. The requirements for the real-time clock are: — the timekeeping shall have an accuracy of 0.02 %; — the correction possibility of the clock shall be not more than 2 minutes per week. Correction for summer and wintertime shall be performed automatically; — correction, automatic or manually, during a trip shall be prevented.