The main function of the hub is to regenerate, shape and amplify the received signal, so as to expand the transmission distance of the network, and at the same time concentrate all nodes on the node centered on it. It works in the first layer of the OSI (open system interconnect) reference model, that is, the "physical layer". Hub, like network card, network cable and other transmission media, belongs to the basic equipment in local area network, and adopts CSMA/CD (carrier sense multiple access technology with collision detection) medium access control mechanism. Each interface of the hub only sends and receives bits. When it receives 1, it forwards 1, and when it receives 0, it forwards 0 without collision detection.
Causes of fluctuation of hub port
1, usually the lack of power supply has nothing to do with the box, but is caused by the weak power supply ability of the USB port of the motherboard.
2. The energy consumption of hard disk is too high.
3. The circuit design of the hard disk box is unreasonable, or accessories such as chips with high energy consumption are adopted-chip performance is often directly proportional to energy consumption. This will lead to a mild power shortage.
4. The USB cable of the hub is too long or too many USB devices are used at the same time. Because USB cable plays a dual role of data transmission and power supply, too long connection will lead to increased resistance and data interference, resulting in insufficient power supply.
How to solve the surge on the hub port
1, the motherboard power is insufficient, there are too many USB devices or the power demand is too great, which leads to an alarm. Plug in several USB devices, especially USB hard disk boxes and USB speakers.
2. System and serial port driver problems, reinstall USB driver.
3. The desktop can change the power box of the host to a higher power point. The USB of the hub is connected to the motherboard, but the motherboard is powered by the main power supply of the host.
The simple solution is to make this hint not appear again, but it doesn't solve the fundamental problem. But it is better than the old pop-up box, and the specific operation is as follows:
(1) Right-click the computer icon and select Device Manager from the pop-up shortcut menu.
(2) After opening the device manager, click "Universal Serial Bus Controller".
(3) It is found that there are two USB management controllers in this PC. Click the first controller and select the Properties button from the shortcut menu that pops up.
(4) Pop up the property setting dialog box, switch to the "Advanced" tab, check "Don't notify me of USB error", and finally click "OK" to complete the setting.
5.USB-IF stipulates that the power supply provided by USB port is 5V/500mA, but at present, many peripherals need more power than this standard. Especially for devices such as external hard disk boxes or mobile hard disks, this situation is easy to occur when using. Sometimes using a long USB cable or using multiple USB devices at the same time may also lead to insufficient USB power supply.