In the previous article, we have discussed Serial and Parallel Transmission. As we know in Serial Transmission data is sent bit by bit, in such a way that each bit follows another. It is of two type namely, Synchronous and Asynchronous Transmission. One of the major differences is that in Synchronous Transmission, the sender and receiver should have synchronized clocks before data transmission. Whereas Asynchronous Transmission does not require a clock but it adds a parity bit to the data before transmission.