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 using a 2 pin shunt supplied with the module. The CH340 USB to serial adaptor makes use of the CH340 USB to serial IC to provide a low-cost alternative to our popular FTDI based module. Although much cheaper this module doesn’t lack in features or usability. The module includes a small switch that allows the voltage available at the VC (Supply output) pin to be switched between 3.3 and 5V. Data pins include TX, RX. These digital pins are at 5V TTL levels allowing them to be directly interfaced with most 5Vmicrocontrollers.