Today there are a large number of port hubs for peripherals which are still used by USB 2.0 sockets. These are ten times slower than the worst 3rd generation ports. Why is a type of interconnect with the worst characteristics still used after all this time? This interface should have been taken off the market years ago, but even so, it is still in use. Because?
USB 2.0 ports are already over two decades old and USB 3.x is old enough that there has been a total replacement of these over time. Since that’s what happened with the 1.x ports of the standard. However, we find that USB-C and USB 3.0 port hubs continue to use them. Honestly, we could all use them if they were the SuperSpeed type. If you ask anyone about the existence of USB 2.0 ports today, the typical answer is cost.
Reality? If we are objective, we will see that the costs of a USB 3.X port are at most higher than those of 2.0. Although that is the fallacy of the olive on the airplane menu. Such a level of savings makes no sense and ends up causing computers to end up having poorer interfaces for peripherals. It is true that if you connect a keyboard, a mouse or some speakers they do not benefit from a USB 3.X port, but neither does 2.0. It is better if there are multiple ports with multi-gigabit per second transfer. However, we find that this is not the case. Why do USB 3.X hubs have 2.0 ports today? Well, even if you don’t believe it, It is not an economic decision, but a technical one..
The 2.0 interface inside your USB 3.X or Type-C
The key is in the way the pins or connectors are distributed in the third generation USB standard
Due to the fact that most devices intended for USB 3.XType A and Type C, no use pins D+ and D- These are totally free to use. The peculiarity is that they are not switched between them. That is, the port can send and receive data from both high-speed pins and other pins at the same time.
What are the manufacturers doing? Well, since they’re not typically used in peripherals, what they do is plug in a USB 2.0 port from each 3.x port which is totally free. Since for every USB 3.X port supporting Hi-Speed USB Controller, that is the reason USB 2.0 ports are still used today. I.e. this is just a side effect of the specification and will continue with USB 4, as it is based on the same pin configuration as Type C .
The special case of virtual reality glasses
In fact, the Data+ and Data- pins yes they are used in some scenarios. It is in the case of USB-C which has the ability to transmit video through the DisplayPor protocolt. Since the necessary transfer is very high, they use the SSTX and SSRX pins for this, so the data transfer ends on the USB 2.0 pins.
Devices that use it? well the virtual reality or HMD headsets be able to connect to PC or console with one cable. While the image is being sent, the D+ and D- pins are responsible for sending the information captured by the sensors integrated in the unit to measure and track control and player movement. As well as to power the internal hardware of the unit.