 Obtaining timing information in this manner, they reliably receive when the transmitter is sending at a slightly different speed than it should.Simplistic UARTs do not do this, instead they resynchronize on the falling edge of the start bit only, and then read the center of each expected data bit, and this system works if the broadcast data rate is accurate enough to allow the stop bits to be sampled reliably.It is a standard feature for a UART to store the most recent character while receiving the next.