This is a high speed USB UART with GPIO.

The CNT-003 is designed for Arduino and has a built-in 100nF capacitor on DTR.

KERNEL=="ttyUSB*",\
    ATTRS{idVendor}=="10c4",\
    ATTRS{idProduct}=="ea60",\
    ATTRS{serial}=="009D5022",\
    GROUP="dialout",\
    MODE="0660",\
    RUN+="/bin/ln -sf %k /dev/ttyCP2104"

/dev/serial/by-id/usb-Silicon_Labs_CP2104_USB_to_UART_Bridge_Controller_009D5022-if00-port0

GPIO bit-bang on the CNT-003 is supported using the CP210x_VCP_Linux_3.13 kernel driver.

Data-sheet