MAX14819 is a dual-port IO-LINK master, and either UART or SPI can be used. The so-called Framer function refers to the function in SPI communication mode where SPI can write data in the transmit and receive FIFO, and the Framer can automatically frame data to be sent out in UART format. When data is received, the data is stored in FIFO in UART format, which can be read via SPI port. This is effectively equivalent to converting data from SPI to UART.