Title: Connection between devices
Course: Appdate yourself 4t ESO (in English) - Curs 2016/17 > Section: Topic 8 Networks

Devices

Connecting wireless devices

Connecting elements in a network or between them without the physical connection of a cable is usually performed using electromagnetic waves. This technology allows for greater comfort and mobility of users.

Electromagnetic waves propagate through space but their power is reduced by the distance between sender and receiver.

This means that the scope of these systems can reach from the tens or hundreds of meters.

Bluetooth is designed to connect computers with low power consumption and a reduced range or distance, allowing the exchange of information between devices and creating small personal networks.

WiFi technology is designed to establish wireless communication between local networks. personal networks.

Wireless connection between devices. Source: Wikipedia.

Both technologies use the same radioelectric frequency;  2.4 GHz, which is the same frequency band as microwaves, but with different encodings of information.

The fact that the transmission is through electromagnetic waves can create problems in information security, which is why communication standards include protection systems using encryption techniques.

Connecting devices to the wireless Internet is also possible with the mobile phone technology GSM and UMTS, which take advantage of the full potential of wireless digital communication.

Wireless communication Bluetooth

Bluetooth connectivity is the most simple communication between devices used in the creation of personal area networks (PAN) and for communication between devices. The scope is limited, as a rule, from ten to a hundred meters at best. With Bluetooth devices like computers, mobile phones, handsfree, printers, digital cameras, GPS navigators, etc can connect.

The communication is established by means of electromagnetic waves at a frequency of 2.45 GHz with a very low power requirement which makes it particularly suitable for portable battery-powered devices which are gettin a transfer rate of 24 Mbps nowadays.

Logotip Bluetooth. Source: Wikimedia

Visit the following interactive on connecting devices to a computer:

Font: Consumer

Look at the following video that shows the benefits of this connection system

The protocol for sending and receiving files using Bluetooth is described in the link.

Activity: With another classmate exchange two photos via Bluetooth from your mobile phones.

Wireless connection WIFI

WiFi stands for Wireless Fidelity, behind which there is a key technology for building local wireless networks, WLAN. WiFi devices can communicate bidirectionally with electromagnetic waves under different standards that define protocols and encryption of data. It has a clear advantage over cable systems because it allows the mobility of devices and use in different networks.

WiFi Logotip. Source: Wikipedia

It uses the same radioelectric frequency  as Bluetooth, 2.4 GHz, with a current transfer rate of 11 Mbps. There are standards which work at frequencies of 5 GHz and 7.3 GHz with transfer rates of 72 Mbps and 54 Mbps.

In the most favorable conditions the maximum range is 300 meters, which can be decreased, however depending on any obstacles. Following certain criteria, coverage can be improved. Have a look at the following interactive activity:

How to improve a WiFi signal. Source: Consumer .

In a local network there are various WiFi access points (WAP Wireless Access Point) that should be strategically located in order to cover the area provided. Access points connect Wifi elements to the local network, so each must have its own IP address which works as an additional element of the network and can only support a limited number of connections.In domestic systems the access point is connected to the same router, which integrates various functions: switch, router and access point.

WiFi. Source: Consumer .

The WiFi connection is usually protected by password to prevent access by unauthorized persons. In some public spaces there are open access areas. Academically there is a network called eduroam (Education Roaming) which is available to universities, research centers and secondary schools in Catalonia and other places in Europe in which students can connect regardless of their training center.

To connect a device to a WiFi network you must follow a specific procedure. Check out the following link:

WiFi is not free of problems which can occur from time to time and one must need to know how to approach them. In thislink there are some guidelines for dealing with these problems.

To protect the privacy of information there are different codes and data encryption for secure networking. The two most common ones are WEP (Wired Equivalent Privacy) and WPA (WiFi Protected Access) and an update of this, WPA2. The safest is the latter incorporating the latest improvements in the field of security.

To find out what encryption is working with a WiFi network, go to the network indicator on your computer and whilst looking at the available lines, hover the mouse over the lines and you will see that the data connection and encryption will appear.

Activity: Find out the connection data and encryption in the school where you are connected.

To find out more security issues, have a look at the following article:

Wireless internet

When a Bluetooth or WIFI connection is not available, an automatic connection through the telephone line is used via 3G or 4G technology.  These lines require specific coverage in a concrete geographical location as well as an available device such as smartphone or USB modem.

The 3G and 4G networks are based on a wireless telephone system named GSM.  The maximum transferring rates are 2 Mbps and 1 Gbps, respectively.

Seeing as this connection service is offered only by commercial operators, its use is closely related to rates and is therefore not free.

Expansion and cost reduction has popularized the use of mobile units,  coupled with  emerging operating systems like Android and its programming tools which have created a new model for using applications (Apps) which give many diverse services to their users.

Later on during this course, you will be working with these applications or Apps.