Telephone call time reminder composed of NE555 and CD4017

At present, my country's telephones implement a time-based charging method in minutes. Except for the first minute, that is, the first period, which is a fixed charge, the charge for one period will be increased immediately after the first second of the next period. For calls that last a long time, the time-based charging of an extra minute is a very small proportion in the billing of the entire call. However, for situations where calls often only need to be completed within 1 minute, even if the call time is delayed by 1 second, the extra charge will account for a very high proportion of the total call charge. The call timer reminder shown in the figure is more meaningful for such calls. The circuit of the timer reminder is shown in the figure. The whole circuit consists of a 6s time base generator, a 6s frequency division timing and display, and a sub-timing and display.