![]() ![]() In this case the hub must be more intelligent, and change its descriptors dynamically to reflect these additional power capabilities, such that the USB host can manage power budget accordingly. The Type-C port therefore provides more options for powering downstream ports. However, Type-C has a native mechanism of providing higher power over USB ports by means of different pull-up values on CC pin, which can indicate port capability up to 3A at 5V, or even 5A if Type-C cable uses "electronic markers". The Type-C connector is not much different with this regard, since four is still bigger than one. If some hub reports fake descriptors (posing as self-powered, while it is not), this will allow to channel multiple full loads from upstream port, and is a brutal spec violation. ![]() It is not "recommended", it is a must, since bus-powered hubs are formally PROHIBITED from supplying more than 100mA/150mA per port, in accord with USB specifications, and the host system will refuse connection to full-powered devices if the hub reports itself as "bus-powered". If somebody wants to have full standard power from downstream ports of a hub to supply all devices, the hub MUST HAVE ITS OWN POWER from a wall adapter. "Standard" USB hubs never can get sufficient power through a single upstream cable, simply because there is only a single connection, which cannot, by very definition, supply four other downstream ports.
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