History of Computers - Serial Communication

Ryder Desenberg

Overview

Serial Communication is the process of sending data one bit at a time. While serial links can not transmit as much data per clock cycle as parallel links, making them appear inferior, a few factors allow them to actually be clocked faster.

Advantages

First, clock skew (sometimes called timing skew) is a phenomenon in synchronous circuits in which the clock signal (sent from the clock circuit) arrives at different components at different times . This becomes a problem when the receiving register gets the clock tick earlier than the sending register. While parallel links can have this problem, Serial links avoid it because they send data one bit at a time, sequentially . Second, with other types of links, electrical interference, or crosstalk occurs. Serial connections take up less space, and therefore reducing the likelihood of crosstalk. In addition, serial links can drive longer distance than parallel buses and are less susceptible to noise . Serial links also offer improved electrical safety in harsh environments .Finally, serial links are cheaper than parallel links.

Disadvantages

1. A serial link would  require faster speeds to transfer the same image, meaning a slower refresh rate.

2. In theory, Serial is slower than  Parallel transmission. However, due to a lack of cross-talk, it can actually be clocked much faster.

Examples of Serial Links

1. Ethernet
2. PCI express
3. RS-232
4. RS-422
5. RS-423

Signifigance

Serial links allow for uncorrupted, long distance, transfer of data. This is the most important aspect of serial links.