The basic idea of a PWM signal is that a signal is switched to 0 or 1 within a certain time interval. The receiving end then measures how long the signal has been at 1. This then results in a range from 0% to 100%. If the signal is 1 at 100 % of the time of the time interval, "100 %" is transmitted. If it is 1 for only 33 % of the time, "33 %" is transmitted. In this case professionals speak of a pulse width of 33 %.
With the type 2 protocol, the charging station thus notifies the vehicle, for example, of the maximum current it is allowed to charge with.