The XR21V1414 USB UART CH B is a USB-to-UART (Universal Asynchronous Receiver-Transmitter) bridge device, commonly used for connecting a microcontroller, embedded system, or other serial communication devices to a PC via USB. It is manufactured by Exar (now part of MaxLinear), and is typically used in situations where a device with a UART interface (such as some microcontrollers, serial devices, or embedded systems) needs to communicate with a PC through a USB port.

The XR21V1414 is an integrated USB-to-serial bridge, which means it acts as an adapter that converts USB signals to UART signals and vice versa. The "CH B" refers to one of the communication channels (usually a specific port or line), often used in devices that support multiple channels for UART communication.