Title: Device Connections
Course: Appdate yourself 4t ESO (in English) - Curs 2020/21 > Section: Topic 6. Networks and Device Connections

Explicació dels diferents tipus de connexions

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 enhanced user comfort and mobility.

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 tens or hundreds of metres.

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

Wi-Fi technology is designed to establish wireless communications in a local network.

Wireless connection between devices. Source: Wikipedia.

Both use the same 2.4 GHz radio frequency, i.e., the same frequency band as microwaves , but with different information encoding. The fact that transmission is via electromagnetic waves can create problems in information security, which is why communication standards include protection systems using encryption techniques .

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

Bluetooth Wireless Connection

A Bluetooth connection is the simplest form of communicating between devices and is used to establish personal area networks (PANs) and for device-to-device connection. The scope is generally limited to tens or hundreds of metres in the best case. Bluetooth enables the connection of devices such as computers, mobile phones, hands-free devices, printers, digital cameras, GPS navigators, computer mice, etc.

Communication is established via electromagnetic waves at a frequency of 2.45 GHz with a very small power requirement, a feature making it especially suitable for battery-powered portable devices. It currently supports a transfer rate of 24 Mbps.

Bluetooth logo. Source: Wikimedia

See the following interactive activity on connecting devices to a computer:

Source: Consumer

Watch the video below for the features of this connection system:

The protocol to send and receive files using Bluetooth is described in this link .

To install Bluetooth devices on a computer, follow the instructions in this link .

Wi-Fi Communication

Wi-Fi is the acronym for Wireless Fidelity, behind which there is a whole technology used to create a wireless local network or WLAN . Wi-Fi devices engage in two-way communication with electromagnetic waves under standards that define different protocols and data encryption systems. They have a clear advantage over wired systems because they enable the mobility of devices and can be used on different networks.

WiFi logo. Source: Wikipedia

Wi-Fi uses the same radio frequency as the Bluetooth system, i.e., 2.4 GHz, and the present transfer rate is 11 Mbps. There are standards that work at frequencies of 5 GHz and 7.3 GHz with transfer rates of 54 Mbps and 72 Mbps.

The maximum range in the most favourable conditions is 300 metres, and it can be less if there are obstacles. Coverage can be improved by following a number of criteria. See the following:

How to Improve Your Wi-Fi Signal Source: Consumer.

Different wi-fi access points (WAPs, Wireless Access Points) are distributed in a local network and must be strategically located to cover the intended area. WAPs establish the connection of the wi-fi elements with the local network. That’s why each one has an IP address as part of the network and can allow a limited number of connections. In domestic systems, the WAP is the router itself, which integrates different functions: switch, router and access point.

WiFi. Source: Consumer.

Connection to a wi-fi network is usually password-protected to prevent unauthorised access. There are areas with free access in certain public spaces. In the academic sphere there is a network called Eduroam (Education Roaming) available at universities, research centres and high schools throughout Catalonia where students can connect, regardless of the centre they are enrolled at.

A specific procedure must be followed to hook a device up to a wi-fi network. See the link.

Problems with wi-fi connections can sometimes occur and you must know how to fix them. See this link for guidelines.

There are different data encryption systems to protect the privacy of information and ensure it travels securely. The two most common are WEP (Wired Equivalent Privacy) and WPA (WiFi Protected Access), and its updated version, WPA2. The last is the most secure and includes the latest improvements in cyber security.

To find out which encryption system a wi-fi network is working with, use the network indicator on the computer to see the ones available. Hover the mouse above them and the connection and encryption information will appear.

For more on security, see these instructions.

Mobile Internet

Where there is no Bluetooth or Wi-Fi internet connection, the connection is made over the mobile phone network with 3G or 4G technology. Connection to these networks requires specific coverage in the particular geographic location and the availability of an access device, whether a mobile phone, smartphone or USB modem .

3G and 4G networks are based on the GSM wireless digital phone system. Their top transfer rates are 2 Mbps and 1Gbps, respectively.

Because this connection service is offered by commercial operators, use is linked to rates and is not free.

Their expansion and the reduction in costs has popularised the use of mobile terminals which, together with the emergence of operating systems like Android and their programming tools, have produced a new model of using applications that provides users with an extensive suite of services. These applications are the so-called Apps you will work on later on.