USB 4 only support USB Type-C ，don't support tranditional Type-A(Standard-A) and Type-B（Micro-B) . Because these ports can't support the transmission speed of 10Gbps and above . USB 4 integate USB 3.2 in terms of function and keep the data of USB 2.0 in the meantime . They two can transmission data in the same time and don't disturb each other . USB 4 is compatible with USB 3.2 and USB 2.0 .
USB 4 and USB 3.2 are all high-speed communication ，the difference is that USB 4 is designed to combine multiple protocols into a single physical interface so that the total speed and performance of the USB4 architecture can be dynamically shared . When transferring USB data ，USB4 allows to parallel running with those separate agreement that dedicated to display (Displayport) , load/ store (PCIe) . USB 4 will expand the bandwidth from 20Gbps （Gen 2x2）of USB 3.2 to 40Gbps（Gen3 x 2) .
USB 4 Gen 3 x 2 is full-duplex and dual-channel data transfer, each channel simultaneously sends and receives data, sending or receiving data at a maximum speed of 20Gbps. USB 4 allocates a maximum of 22Gbps of bandwidth for data transfer and a minimum of 18G for display support 。It can connect the monitor with resolution of 5120x2880(5k) and refresh rate of 60Hz and color depth of 30bit ，the rest bandwidth of 18Gbps is used for data transmission . Or it can connect two monitor with resolution of 4096x2160(4k) and refresh rate of 60Hz and color depth of 30bit ，the rest bandwidth of 8Gbps is used for data transmission .