Can you clearify your USB data flow? You have two USB input channel, microphone and electromagnetic board, what's their target host device? Two output USB channel, what's their target host device?
Which device is 讲台？A USB hub would only have one upstream port and several parallel downstream port.
We need more text explanation about your application.
Sorry, reply so late.
We had in-depth discussionts with the customer enginner, we just take the type-c part, Type-C1 and Type-C2.
Simple flow of system work:
a) Laptop output video, display to the platform(LCD) and black board.
b) When there is no laptop, black board output video, display to the platform.
a) receive video from laptop;
b) power the laptop, 45W/60w.
a) output the video to the black board;
b) receive video from the black board, type-c2 is two-way video.
For type-c1 and type-c2, Please recommend a suitable plan, ths.
For dual-port Type-C application, you can choose CCG4. We do not have similiar application but you can take a look at this reference design. In this reference design, one Type-C port is upstream port and another is downstream port.
If the customer do not have legacy charge requirement, then CCG4 would be suitable.
If we're only responsible for type-c1 and type-c2, can we simplify separate designs?
For type-c1, just power the computer and receive the video from it, apply as follow diagram.
We could select CCG3.
For type-c2, need two-way video（双向视频信号）
How to acheive two-way video, could you give me some advice?
You should choose the right chip based on the cost. Of cource you can use two CCG3 if you want the billboard function. But two CCG3 is more expensive than one CCG4.
Two-way video depends on the DP-Mux you choose. In your diagram, the DP-MUX is missing. For any Type-C receptable designs, a mux is needed. Or if you design a Type-C plug, there is no need for a Dp mux. We have firmware of CCG3 and CCG4 support two-way DP signal.