The reader initializes the conversation. The RF discipline is activated, and several other lower stage commands are exchanged to detect a appropriate card. 1x GND 3V3 (P2 with 2 pins 2.54mm) connector can be employed to energy externally the WCH CH569 MCU (it is usually recommended to remove the P4/SHUNT https://hydrabus06283.nico-wiki.com/1248260/hydrabus_things_to_know_before_you_buy