100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
logo-home
1.3 Data Transmission £5.49   Add to cart

Lecture notes

1.3 Data Transmission

 25 views  0 purchase

Full notes for module 1.3 Data Transmission

Preview 1 out of 8  pages

  • June 11, 2019
  • 8
  • 2016/2017
  • Lecture notes
  • Unknown
  • All classes
book image

Book Title:

Author(s):

  • Edition:
  • ISBN:
  • Edition:
All documents for this subject (12)
avatar-seller
luca_pass
AS Computing
Unit 1.3 Data Transmission
We usually use telephone lines to connect to the internet. We communicate packets along these
lines which contain:
 Transmitted data
 Delivery address
 Sender ID
 Recipient ID
Webpages are held on servers which are computers specialised for web processes. The files are held
here and a user can then access this server to view the page.
We call the web such because there are so many networked computers on it if you mapped them
out it would look like a spider’s web.
Why do we even need to transfer data individually?
 Computers are digital – They can’t transfer data any other way
 Previously we would use letters to transfer data – It would be way to slow
 It can prevent spelling mistakes
In short:
 We need a quicker way
 We needed a way that would trap errors
 We needed a way that would make sure that a message got through
Synchronous and Asynchronous Transmission
There are two types of transmission, synchronous and asynchronous.
Synchronous
 Synchronous transmission does not use start and stop bits
 A bit stream is combined into longer frames that may contain numerous bytes
 There are no gaps between bytes in a data stream
 In the absence of start and stop bits, bit synchronisation is established between the sender
and receiver by timing the transition of each bit
 Since various bytes are place on the link without any gap, it is the responsibility of the
receiver to separate the bit stream into bytes so as to reconstruct the original information
 In order to receive the data error free, the receiver and sender operate at the same clock
frequency
Asynchronous
 Asynchronous transmission only sends one character at a time, i.e. only one byte.
 Bit synchronisation between two devices is made possible using a start & and end bit
 The start bit usually indicates the beginning of data i.e. alerts the receiver to the arrival of a
new group of bits. A start bit usually 0 is added to the beginning of each byte
 Stop bit indicates the end of data i.e. to let the receiver know that byte is finished, one or
more additional bytes are appended to the end of the byte. These bits usually 1’s are called
stop bits.




Page |1 Luca Passariello AS Computing

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

Guaranteed quality through customer reviews

Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.

Quick and easy check-out

Quick and easy check-out

You can quickly pay through credit card for the summaries. There is no membership needed.

Focus on what matters

Focus on what matters

Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!

Frequently asked questions

What do I get when I buy this document?

You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.

Satisfaction guarantee: how does it work?

Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.

Who am I buying these notes from?

Stuvia is a marketplace, so you are not buying this document from us, but from seller luca_pass. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for £5.49. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

73216 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now

Start selling
£5.49
  • (0)
  Add to cart