This diagram shows the timing and DFFs for the UART signal. In the top circuit, the signal is taken the DFFs and then passed on to a timing circuit which triggers the DFFs at the appropriate baud rate. The 12 bit counter allows us to keep track of time at the same rate that it is being sent by the RS232 port. Each time signal that represents a new data signal triggers the DFFs which reads the next value. The DFFs then connect their output to a bus which is called q and represents the data being transmitted.