Exar's XR21B1421 and XR21B1424 are enhanced UART bridge to USB interfaces. The one channel XR21B1421 uses HID class USB interface. Fully compliant to the USB 2.0 (Full-speed) specification with 12 Mbps USB data transfer rate, the USB interface also supports USB suspend, resume, and remote wakeup operations. The USB Vendor ID, Product ID, power mode, remote wakeup support, maximum power, and numerous other settings may be programmed in the on-chip OTP memory via the USB interface using either HID reports or Exar supplied OTP programming tools.