18. CAMBRIDGE IGCSE (0478-0984) 2.1 Data transmission methods

Summary

This video explores various data transmission methods, including simplex, half duplex, and full duplex, along with the concepts of serial and parallel transmission. It discusses the differences between these methods, highlighting their applications in devices like computers and printers. Simplex allows data flow in one direction, half duplex allows two-way communication but not simultaneously, and full duplex enables bidirectional transmission at the same time. The video also contrasts serial transmission, commonly used in USB, with parallel transmission, explaining the pros and cons of each, such as speed, distance limitations, and reliability.

Takeaways

• 😀 Simplex transmission allows data to travel in only one direction, such as from a computer to a monitor.
• 😀 Half duplex transmission enables data to travel in both directions but not at the same time, like with parallel printer cables.
• 😀 Full duplex transmission supports simultaneous two-way communication, commonly found in network cables used in LANs and the internet.
• 😀 Serial transmission sends data one bit at a time over a single cable, offering minimal interference and better reliability over longer distances.
• 😀 Parallel transmission transmits multiple bits simultaneously along multiple cables, making it faster for short distances but prone to issues like data skew.
• 😀 Skew in parallel transmission occurs when bits travel at different speeds due to wire imperfections, causing them to arrive out of sequence.
• 😀 Serial transmission is now widely used with interfaces like USB, which are simple and cost-effective.
• 😀 Parallel transmission, though faster in the past, has been largely replaced due to its limitations over long distances and data skew.
• 😀 The direction of data transmission can be simplex, half duplex, or full duplex, affecting how data is transmitted between devices.
• 😀 To prepare for exams, it's crucial to understand the differences between serial and parallel transmission methods and their advantages and drawbacks.

Q & A

What is simplex transmission?

Simplex transmission is a data transmission method where data can only travel in one direction, such as from a computer to a monitor.

How does half duplex transmission differ from full duplex transmission?

In half duplex transmission, data can travel in both directions but not at the same time, while in full duplex, data can travel in both directions simultaneously.

What is an example of a situation where half duplex transmission might be used?

Half duplex transmission might be used with parallel printer cables, where data is sent to a printer and the printer responds with an error code, but not simultaneously.

Why is full duplex the most common form of data transmission?

Full duplex is most common because it allows data to travel in both directions at the same time, which is essential for many modern communication systems, such as LANs and the internet.

What is the main difference between serial and parallel data transmission?

In serial data transmission, individual bits are sent one at a time over a single cable, whereas in parallel transmission, multiple bits are sent simultaneously over multiple cables.

What are the advantages of serial transmission over parallel transmission?

Serial transmission has minimal interference, is simpler and cheaper to produce, and is more reliable over long distances.

Why is parallel transmission faster than serial transmission in some cases?

Parallel transmission can send multiple bits at once across multiple cables, which allows for faster data transfer compared to sending one bit at a time in serial transmission.

What are the disadvantages of using parallel transmission over long distances?

Parallel transmission is prone to interference and can suffer from a problem called 'skew,' where bits travel at different speeds and arrive out of order, making it unreliable over long distances.

Why are parallel cables rarely used today?

Parallel cables are rarely used today because of their limitations, such as skew, interference, and their inability to handle long-distance transmissions effectively.

What is skew in parallel transmission, and why is it a problem?

Skew occurs when the bits in a parallel transmission travel at different speeds and arrive out of sequence, causing data to become corrupted. This problem limits the use of parallel transmission to short distances.