USB stands for Universal Serial Bus.USB is an industry-standard for short-distance communication like between computer and keyboard, computer and mouse, monitor and mouse, the monitor to the laptop, printer and computer, etc.USB devices are nowadays everywhere because of easy configuration and procedure to connects the devices.USB System has two types of ports ie. Downstream port and Upstream port. In this article, I will be explaining to you the Downstream port, Upstream port, their use case in the monitor, etc.
Before talking about those ports, let's know one thing and that is. HDMI, RJ45 port only sends data to the respective devices but USB ports are capable of carrying power and data. Due to which USB gadgets do not need an extra cable for power.
Upstream ports receive power and data from the host. In the case of a standalone monitor, the host is a desktop PC / laptop and an upstream port is present in the standalone monitor. If a desktop PC or laptop is a Host and they generally have Type A Connector and Upstream Port in a standalone monitor have Type B Connector(ie. upstream connector). These are connected with the help of the following cable consisting of both Type A and Type B ports.
As power and data are received by the monitor from Desktop PC / laptop so, the content of the laptop and desktop will be visible on the monitor. Therefore, the Upstream port is present in the monitor. This doesn't means that the monitor does not require power. Monitors need extra AC mains cable to plug into an outlet. But if you consider thunderbolt and USB Type C port based monitor which may not need extra power cable because they can drive enough power to an LCD monitor.
Downstream Port sends data and power to the devices like keyboard, mouse, standalone monitor, etc. In monitor there is a downstream port as well, if you want to connect peripherals like a mouse, keyboard, speaker, flash drive, etc then you can connect to the Downstream port present in Monitor. Downstream Port sends power and data to those external peripheral.USB supplies power at 5 V to power USB downstream devices.
In most of the standalone hp and dell monitors, there is both upstream and downstream port available. The upstream port receives data and power from the host (generally desktop PCs or laptops). In these types of monitor, there should be a hub in between which connects the upstream port and downstream port. So, commonly there will only be one Upstream port and multiple Downstream ports in the monitor.
My Recommendation: If you want to connect a monitor for viewing the computer's video display then the USB port with Type A and Type Bis is not good. If the data port is Type C and Thunderbolt type then it is ok for video. Generally, prefer port for video is HDMI and DP.