| NS 16550
This is the modern UART chip found in standard PCs. The communications
port on the first IBM PC was built around a National Semiconductor UART
that could hold only 2 bytes of received data. As modem speeds increased,
this limit caused problems (any byte of data received before the 2 bytes
were processed would be lost). More modern UARTs are compatible with
National Semiconductor's 16550 family of chips that hold 16 bytes before
losing data. |