Features: This adapter uses main chip, generating virtual serial port after installing driver. Powered by USB, with 3.3V and 5V voltage output power, and there are all useful pins. Designed with self-recovery fuse, which can effectively protect your downloader and computer USB port in the case of accidental short circuit. Integrated status indicator and transceiving indicator; status indicator light will be normally on after installing driver correctly, transceiving indicator light will flash during communication, the higher the baud rate is, the lower brightness will be. Designed with male USB connector, can be directly connected to computer USB port. Specification: Type: USB to TTL Support Baud Rate: between 300bps and 1Mbps. Supported Communication Formats: 1) 5,6,7,8 bits of data; 2) support 1,1.5, 2 stop bits. 3) odd, even, mark, space, none parity Supported Operating System: For windows 8.1/7/vista/xp/98, for MacOS-X/OS-9, for Linux Size: 4.8*1.5cm / 1.9*0.6in Weight: 5g / 0.2oz (approx.) Package list: 1 * USB to TTL Module General Knowledge: TXD: Transmitting data, must connect to RXD of another equipment for normal communication. RXD: Receiving data, must connect to TXD of another equipment for normal communication. TXD always connects to RXD of other equipment for normal communication. Self-transceivingFor normal communication the RXD connects to TXD of other devices, so if need to receive their own data, directly connect its own RXD and TXD together. It is used to test whether the transmitting and receiving is normal, and is the simplest and the fastest test method first to do when there is a problem.Also known as the loopback test. Level logic: TTL level: Data representation usually adopts binary, + 5 v is equivalent to a logic "1", and 0V is equivalent to logic "0", known as the TTL signal system, is the positive logic. RS232 level: -12V to 3V is equivalent to a logic "0", while +3V to +12V logic level is equivalent to a logic "1", is a negative logic. 1、This adapter uses main chip, generating virtual serial port after installing driver. 2、Powered by USB, with 3.3V and 5V voltage output power, and there are all useful pins. 3、Designed with self?recovery fuse, which can effectively protect your downloader and computer USB port in the case of accidental short circuit. 4、Integrated status indicator and transceiving indicator; status indicator light will be normally on after installing driver correctly, transceiving indicator light will flash during communication, the higher the baud rate is, the lower brightness will be. 5、Designed with male USB connector, can be directly connected to computer USB port.