I took ximeng's interpretation of my comment yesterday and worked on it. Here's my newest attempt at the USB-C explanation. A. The USB C cable physically consi

I took ximeng's interpretation of my comment yesterday and worked on it. Here's my newest attempt at the USB-C explanation. A. The USB C cable physically consists of: 1. 60/100W power wire pair 2. USB2 speed data wire pair supporting 0.48Mbit/s 3. 4 high speed data wire pairs (“high speed lanes”). These can be ommitted. Each high speed lane supports at least 5/10Gbit/s depending on cable length. 4. Separate wire for negotiating power roles (source/sink) and data roles (upstream/downstream or host/peripheral). 5. eMarker cables are required for rapidly changing wattage of power supply (Programmable Power Supplies, PPS) B. Protocols (all over high speed lanes apart from USB2): 1. USB. 480mbit/s over the dedicated pair is always possible. 5/10gbps USB using two high speed lanes is the default mode for the high speed lanes depending on cable length. (four high speed lanes at 20gbps theoretically possible but rarely supported by hosts) 2. DisplayPort 1.2 (8.64Gbit/s video data over 2 high speed lanes) / DisplayPort 1.3/1.4 (12.96Gbit/s over 2 high speed lanes, double over 4). MST technology allows splitting the aggregate video data bandwidth across monitors but Mac doesn't support this. DisplayPort 1.4 supports video compression, but this is rarely supported by monitors. If using only 2 high speed lanes the other 2 can be used for USB data. This mode doesn't require any protocol converter to connect a DisplayPort device, only a simple USB C controller to negotiate DisplayPort mode. The USB C pins become DisplayPort pins, essentially. 3. Thunderbolt 3/4 (needed for Mac dual monitors). Thunderbolt 4 is USB4 with optional features mandatory (however in practice these optional features are likely to always be included so they can be treated as the same). TB3 carries PCI Express + DisplayPort packets, TB4 also native USB packets. Thunderbolt controllers are required on both ends. In a TB3 dock, this controller provides the USB root hub, in TB4 the USB data comes from the host. Bus bandwidth is maximum 40gbps, depends on host and cable both (this is why TB peripherals ship with so short cables). The bus can have two independent DisplayPort connections (which PCs can again split to even more). Laptops with TB4 and/or two Thunderbolt ports always have two, most TB3 laptops with a single port will only provide one -- and that one will only be DP 1.2. Note two ordinary independent DP cables can carry 51.84Gbit/s worth of video data (if the host and monitor both supports at least 1.3) but the TB bus is limited to 40Gbit/s. Finally, power: 5/9/15/20V. Requirements signaled by resistors on the device side if only 5V. More than 5V negotiated between devices: 1. Agree source and sink, by default the data upstream/host is source but this can be negotiated, 2. Source indicates how much power it can provide, either 3A or with a 20V cable optionally 5A. This assumes fixed power, some devices now support PPS.