Connection characteristics Skills: none IT concepts: wired and wireless connections, connection technologies, connection length and speed, units of measure for amount of data and connection speed This work is licensed under a Creative Commons Attribution-Noncommercial- Share Alike 3.0 License.

Where does this topic fit? Internet concepts –Applications –Technology (communication) –Implications Internet skills –Application development –Content creation

Is the connection wired or wireless? What technology does the connection use? How long is the connection? How fast is the connection? Connection characteristics Computer 1 Computer 2

Wireless connection technologies Satellite radio Terrestrial radio

Wired connection technologies Copper, twisted pair (electronic) Copper, coaxial cable (electronic) Fiber (optical)

Only use wireless connections when a wired connection is not practical.

Connection length

Connection speed Computer 1 Computer 2 How fast can it transmit data?

Some units of measure Timeminutes Distanceinches Weightpounds Amount of databits Can you think of others?

What is a bit? A bit is a binary digit, it may take on one of two values, 0 or 1: 0 1 All data types – numbers, images, audio, video, images, etc. are encoded as bits!

Larger units of amount of data Bita single 0 or 1 Kilobit1,000 bits Megabit1,000,000 bits Gigabit1,000,000,000 bits Terabit1,000,000,000,000 bits Petabit1,000,000,000,000,000 bits (These are approximate. A kilobit is actually 1,024 bits, a megabit 1,024*1,024 bits, etc., but this is close enough for most discussions).

One more -- what is a byte? 8 bits, for example:

Connection speed Computer 1 Computer 2 How fast can it transmit data? How many bits can be sent from one computer to the next in a given amount of time?

Units of measure for a rate (velocity) Timehours Distancemiles Velocitymiles/hour miles/hour = “miles per hour” the distance traveled in one hour Distance/time Can you think of others?

Units of measure for a rate (data transmission speed) Timeseconds Amount of databits Transmission ratebits/second bits/second = “bits per second” the number of bits transmitted in one second amount of data/time Can you think of others?

A few questions

We discussed four characteristics of a communication link. Without looking back, do you recall what they were?

What is a unit of measure for: Weight Length Rate at which you run Amount of data Rate of data transmission What are two other units of measure for each of the above?

The general form of a unit of measure for velocity is distance/time. What is the general form of a unit of measure for data transmission speed?

How many bits in a megabyte? How long would it take to transmit a 100 megabit file over a 100 megabit/second communication link? How long would it take to transmit a 100 megabit file over a 10 megabit/second communication link? How long would it take to transmit a 100 megabit file over a one gigabit/second communication link? How long would it take to transmit a 100 megabyte file over a 100 megabit/second communication link? How long would it take to transmit a 100 megabit file over a 100 megabyte/second communication link?

This is a 2.03 megabyte image How many megabits is that? How long would it take to download this image over a 1 megabit per second connection? How long would it take over a 1 gigabit per second connection?

Connection characteristics Skills: none IT concepts: wired and wireless connections, connection technologies, connection length and speed, units of measure for amount of data and connection speed This work is licensed under a Creative Commons Attribution-Noncommercial- Share Alike 3.0 License.