This is CH340G USB to TTL (serial) converter, USB to TTL / USB-TTL / STC microcontroller programmer / PL2303 in nine upgrades plate with a transparent cover Compatible with ARDUINO, RASPBERRY PI, AVR, PIC, 8051, etc.

This USB-TTL converter is based on CH340G USB to serial TTL converter chip. The module can be used for 3.3V logic level signals, and has the option to switch from 5V to 3.3V logic level by using a 2-pin shunt which comes with the module.

The CH340 USB to Serial Adapter uses the CH340 USB to Serial IC to provide a low cost alternative to our popular FTDI based module. Although much cheaper, this module is not lacking in features or usability. Once you install the drivers, the module will appear as a normal serial COM port on your computer, making it compatible with most terminal programs and development environments such as the Arduino IDE.

The module includes a small switch that allows the voltage available on the VC (Supply output) pin to be switched between 3.3 and 5V. Data pins include TX, RX. These digital pins are at a TTL level of 5V, allowing them to be interfaced directly to most 5V microcontrollers.

1….5V (USB)
2….VCC (Input, connect to 5V or 3V3 pin via jumper)
3….3V3 (*measured at 3.67V)
4….TXD
5….RXD
6….GND