Shop name:Chong Qing Shuo Yue Ke Ji You Xian Gong Si Full-speed USB device interface, compatible with USBV2.0. Built-in firmware emulates standard serial ports and is used to upgrade serial port peripherals or add additional serial ports via USB. the serial port application program under the Windows on the computer side is fully compatible and does not need to be modified. Supports installation-free built-in CDC class driver or multi-functional high-speed VCP manufacturer driver. Hardware full-duplex serial port, built-in transceiver buffer, supports communication baud rate 50bps ~ 6Mbps. Optional automatic identification and dynamic adaptation of common communication baud rates at 115200bps and . The serial port supports 5, 6, 7 or 8 data bits, and supports odd parity, even parity, blank, flag and no parity. Supports commonly used MODEM contact signals , DTR, DCD, RI, , . Support and hardware automatic flow control. Support half-duplex, provide sending status TNOW and support RS485 switching. By adding an external level conversion device, the RS232 interface is supported. the USB side supports 5V power supply voltage and 3.3V power supply voltage. The serial port I/O is independently powered and supports 5V, 3.3V, 2.5V, and 1.8V power supply voltages. Built-in power-on reset, built-in clock, no external crystal oscillator required. the chip has built-in Unique ID (USB Serial Number). Available in SOP16, ESSOP10 and QFN16 lead-free packages, RoHS compliant. Description: Instructions for use The 5V and 3.3V outputs can be switched via . (Note: Direct connection of 3.3V and 5V will burn the board, confirm the level before connecting) 1. If the jumper is between and +5V, the high level of TXD and RXD output is 5V. 2. If the jumper is between and 3V3, the high level of TXD and RXD output is 3.3V. (Different batches may have differences in product appearance, color, and printing, which do not affect use) size: 40mm x 19mm Material: PCB colour: As shown Package Contents: 5 x CH343G USB to Serial Port Module, 5 x 4Pin Bent Pin, 5 x 3Pin Bent Pin and Jumper Cap Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.