3M Baud Rate USB to TTL Serial Port Module 3.3V/5V Level CH343G Chip CDC Class Driver with Circuit Protection Indicator Light

1. Power indicator light: It is normally on when the power supply is normal2. 3.3V/5V toggle switch: used to switch signal levels and VCC voltage. It is recommended to operate it when powered off.3. CH343 serial port chip4. RXD indicator light: Data reception indicator light, which flashes when data is being received at the TTL terminal.5. TXD indicator: Data transmission indicator, flashes when data is being transmitted on the TTL port.6. CTS indicator light: This is a transmission permission indicator light, which is constantly on when the input is valid.7. RTS indicator light: Request to send indicator light, constantly on when outputting effectively. 8. VCC: Power output positive terminal, capable of outputting 5V/3.3V9. RTS: Used to indicate that the device is ready to receive data, and is active when at a low voltage level.10. CTS: Used to determine whether data can be sent to the other party, active low.11. TXD: Serial data output12. RXD: Serial Data Input13. GND: Power output negative pole14. RI: MODEM contact input signal, ringing indicator, active low15. DSR: MODEM contact input signal, data device ready, active low16. DTR: MODEM contact output signal, data terminal ready, active low During power-on, if an external pull-down resistor is detected, it will switch to serial port transmission to indicate the status of ongoing operations, with high level being valid. 17. DCD: MODEM contact input signal, carrier detection, active low18. DOWN: Pull-down resistor connection terminal. During power-on, it can be connected to pins 16 and DTR via a dupont wire, switching it to the TNOW output pin to indicate that the serial port is sending data. In half-duplex mode, TNOW can be used to directly control the transmit-receive switching of the RS485 transceiver. 19. ACT: USB configuration completion status output, which can be used to notify the MCU or drive the light-emitting diode connected to VIO after a current-limiting resistor is connected in series. It is active at low level and inactive when suspended.

• Adopting CH343G chip, full speed USB 2.0 device interface, supporting baud rate range: 50bps -3Mbps, multiple circuit protection
• Built in clock, the allowable baud rate error for serial signal reception is not more than 4%, and the baud rate error for serial signal transmission is less than 1.6%
• Support installation free operating systems with built-in CDC class drivers or multi-functional high-speed VCP vendor drivers
• The VCC pin and signal pin support multiple voltage options of 5V and 3.3V, which can be selected through the onboard dip switch. Please switch the voltage value through the dip switch when the module is powered off
• Five white indicator lights are installed on the board, with reserved hardware flow control pins DTR, DCD, RI, DSR, and USB status pin ACT for easy external control of other devices