CH340 3.3v-5v TTL USB Serial Port Adapter

A simple USB to serial converter with selectable voltage through a jumper. Specifications:

• 3.3V-5V TTL voltages
• Power supplies: 5V, 3.3V, GND (min)
• RX (3.3V-5V)
• TX (3.3V-5V)
• Chip: CH340 (drivers)

With the supplied jumper you can configure the module for 5V or 3.3V. Without the jumper, the module is automatically powered with 3.3V. For 5V you have to put the jumper between the Vcc and 5V.
If you want to change the voltage, first disconnect it from a computer so that there is no voltage on the module.