Metal USB uses a four-wire cable, two of which are used to transmit data to the serial channel, the other two for the downstream (Downstream) equipment to provide power for any successful connection and mutual recognition of the peripherals, both devices will be able to support The highest rate of transmission of data. The Metal USB bus automatically switches from high speed to low speed dynamically in the compatible transmission mode according to the peripheral conditions and matches the lock at the appropriate rate. Metal USB is based on the token's bus. Similar to the Token Ring network or the FDDI token-based bus. Metal USB host controller broadcast token, the device on the bus detects whether the address in the token matches itself, by receiving or sending data to the host to respond. Metal USB manages Metal USB bus power by supporting suspend / resume operations. The Metal USB system uses a cascaded star topology, which consists of three basic parts: a host, a hub, and a functional device.
The host, also known as the root, root node or root hub, is done on the motherboard or as an adapter card installed on the computer, the host contains the main controller and root hub (Root Hub), control the Metal USB bus data and Control the flow of information, each Metal USB system can only have a root hub, it is connected to the main controller, a computer may have multiple root hub.
The hub is a specific component of the Metal USB structure that provides a point called a port that connects the device to the Metal USB bus and detects the devices connected to the bus and provides power management for those devices, responsible for bus fault detection and recovery The The hub can provide energy for the bus and provide energy for itself (power from the outside).
The functional device is connected to the bus via port. Metal USB can be used at the same time Hub.