For example, in the DTIM3 mode, the modem is silenced for 300 ms and then activated for 3 ms. The Wi-Fi modem is stopped while maintaining a Wi-Fi connection without data transmission to optimize power consumption. Modem Sleep Modem-Sleep mode is used in applications that require processor operation, as in PWM or I2S applications.They are detailed in the official documentation page 6 Different sleep modes and power consumption of an ESP8266EX module