What is the difference between USB and USB OTG?
USB OTG is the abbreviation of USB On-The-Go, which is mainly used for the connection between various devices or mobile devices for data exchange. That is, Windows Phone devices can be allowed to connect to flash drives, external USB hard drives, keyboards, and even mice through the USB interface, but this generally requires the use of a special adapter cable to establish the connection.
The characteristics of USB’s low power consumption, easy connection and high-speed transmission have made it an easy-to-apply architecture, and new applications will be born when it is combined with other technologies. For example, in the field of mobile storage, the combination of USB and flash memory creatively gave birth to the currently popular mobile storage device-U disk.
The USB data cable is used to connect the mobile phone and the computer, and the photos and music in the mobile phone can be accessed through the computer, and the mobile phone can be used as a U disk. The OTG data cable does not require a PC, and the mobile phone can be directly connected to USB devices such as U disk, mouse, and keyboard through the OTG data cable. Connect the USB flash drive to find the information directly, connect the mouse to play games, connect the keyboard to type quickly, connect the camera to browse the pictures directly, and upload immediately. OTG expands the functions of mobile phones.
The difference between the OTG cable and the ordinary USB cable is that when the USB data cable is connected to the computer, it is powered by the computer, and when the OTG data cable is connected to a USB flash drive and other devices, the mobile phone must supply power to the USB flash drive and other peripherals, so how does the mobile phone recognize the USB data? Cable and OTG data cable? After disassembling the two wires, you will find that the 4th pin of the USB data cable is floating, and the 4th pin of the OTG data cable is shorted to the ground. The mobile phone chip should judge whether the inserted OTG data cable or the USB data cable is inserted through the 4th pin. , And use this to decide whether to turn on OTG power supply.
The difference in hardware is that there is a PIN at one end of the OTG cable and a GND wire to allow the machine to distinguish who is the HOST host and who is the Device peripheral. The appearance alone cannot distinguish the difference between the OTG cable and the ordinary USB cable.