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A USB-to-serial adapter or simply USB adapter is a type of protocol converter that is used for converting USB data signals to and from serial communications standards (serial ports). Most commonly the USB data signals are converted to either RS-232 , RS-485 , RS-422 , or TTL-level UART serial data.
A USB device can be located by the bus:device address, or by the hub:port address. [16] Also, after the descriptors is retrieved, the host performs another control transfer exchange, but instead to set the address of the USB device to a new ADDRx.
The throughput of each USB port is determined by the slower speed of either the USB port or the USB device connected to the port. High-speed USB 2.0 hubs contain devices called transaction translators that convert between high-speed USB 2.0 buses and full and low speed buses. There may be one translator per hub or per port.
Finally the call device.controlTransferOut() will set up the device to communicate through the WebUSB Serial API. Once the set up is all done, data can be transferred to the device using device.transferIn() to transfer bulk data to the device, similarly its sister function device.transferOut() to read data from the device. [17] [1]
To allow for voltage drops, the voltage at the host port, hub port, and device are specified to be at least 4.75 V, 4.4 V, and 4.35 V respectively by USB 2.0 for low-power devices, [a] but must be at least 4.75 V at all locations for high-power [b] devices (however, high-power devices are required to operate as a low-powered device so that they ...
Almost all ports on personal computers are hot-swappable. Plug-and-play ports are designed so that the connected devices automatically start handshaking as soon as the hot-swapping is done. USB ports and FireWire ports are plug-and-play. Auto-detect or auto-detection ports are usually plug-and-play, but they offer another type of convenience.
In addition, some types of computer systems do not treat USB devices as hot-pluggable, which means the keyboard and mouse will not be re-detected when switching back to a particular KVM port. For these types of systems, it is necessary to implement device emulation. Standard device emulation has its limitations.
A four-port "long cable" "external box" USB hub A four-port "compact design" USB hub: upstream and downstream ports shown. A USB hub is a device that expands a single Universal Serial Bus (USB) port into several so that there are more ports available to connect devices to a host system, similar to a power strip. All devices connected through a ...