1 Computer Maintenance Mobile Devices: How they Operate Copyright © Texas Education Agency, 2013....

1

Computer Maintenance

Mobile Devices: How they Operate

Copyright © Texas Education Agency, 2013. All rights reserved.

Course Objectives

Define and identify what constitutes a mobile device

Demonstrate a working knowledge of mobile device operation

Understand and explain how mobile devices communicate

Copyright © Texas Education Agency, 2013. All rights reserved. 2

Mobile Devices

Mobile device: a small, hand-held computing device that typically weighs less than 2 pounds


Types of Mobile Devices

Cell phones Smart phones Personal data assistants Tablet (more recently)


Mobile Devices

Devices contain an operating system that allows them to run smaller applications called apps.

Wireless connectivity is built into the device Wi-Fi Bluetooth Cellular


Mobile Device Interface

Touch: Device interaction by touch can happen in many different ways: Touchscreen Stylus Mechanical keyboard & finger track pad/ball



Touchscreen: Screen of the device contains layers with the LCD being on the bottom and the subsequent layers above house the touch sensors Two most widely used systems in mobile devices:

Resistive and Capacitive Touch The screen is comprised of a

large grid that signals the coordinates of the user’s input



Resistive Touch: Two thin layers where one is electrically charged and the other senses the charge when the two are pressed together This is an older version of the touchscreen

technology. Pressing firmly on the screen and using a stylus

were the two most common means of using this technology



Capacitive Touch: An insulator (glass) is coated with a grid of conductors that emit an electrostatic field that when touched allows the grid to locate where the field is being disrupted This is the current standard for touchscreen

interfaces (smartphones, tablets, and other current mobile devices). Doesn’t require firm presses—merely a light touch Requires touch with skin (conductive) to function


Operating a Mobile Device

Device Operation (Smartphone): Power button

Turns the device on/off Home button – Usually located on a central part

of the device Turns the screen on Exits an application May be a Back button


Operating a Mobile Device

Device Operation (Smartphone) Cont’d: Back button (may also be the home button)

Exits an application / Reverts to a previous screen Track pad – Some devices have this option also

located in a central part of the device. Utilized to navigate on devices without a touchscreen


Mobile Devices – How They Communicate Mobile devices use three means of wireless

communication: Wi-Fi, cellular, and Bluetooth Wi-Fi is used for small coverage areas

Residential Businesses

Cellular is used for large geographical areas Deployed by large telecom companies

Bluetooth is for the smallest coverage areas Often utilized as an accessory device alongside

mobile devices (ex. Bluetooth headset)


Mobile Devices – Wi-Fi

Wi-Fi: Wireless technology that allows electronic devices to exchange data

Wi-Fi (a.k.a. WLAN) was developed in the mid to late 1990s

Developed by the technology that allows devices to transmit and receive data wirelessly through radio frequencies

Requires an Internet source to function as a router (hub) and offers Internet connectivity to wireless devices

Utilizes a standard that can connect with almost all mobile wireless devices


Mobile Devices – Wi-FI The different speeds of Wi-Fi

802.11b - Single Band Late 90s technology – 2.4 Ghz - 11 Mbits/s

802.11g – Dual Band Unified b/g 2003 standard – 2.4 Ghz – 54 Mbits/s

802.11n – Dual Band 2009 amendment – 2.4 & 5 Ghz – 54 to 600 Mbits/s

802.11ac – Fifth Generation of Wi-Fi – An emerging standard 5 Ghz – At least 1 gigabit per second


Mobile Devices – Wi-Fi Wi-Fi Security

Wired Equivalent Privacy (WEP): Initial form of Wi-Fi security; introduced in 1999 and outdated by 2003 due to security concerns (least secure)

Wi-Fi Protected Access (WPA): 2003 security implementation designed to make wireless networks more secure

Wi-Fi Protected Access 2 (WPA2): Current security standard that employs a 256 bit encryption (most secure)


Mobile Devices – Wi-FI Wi-Fi Security: Connecting to the network

Select network name Identify security type

Mobile device should auto detect the security type Enter password Join


Mobile Devices – Cellular Cellular wireless: Wireless connectivity via

cellular radio towers that are deployed across an extensive geographic area Providers utilize different technologies that can

allow devices to work with one provider and not another

Current cellular technologies are CDMA and GSM and LTE

Cellular wireless speeds are increasing rapidly due to the benefits of the newest technology, LTE


Mobile Devices – Cellular

Cellular wireless cont’d: Broadcast from the 450 Mhz frequency up to the 21

MHz frequency FCC oversees who owns what frequencies a cellular

provider may utilize Lower frequencies allow a cellular radio tower a

greater radius of range Lower frequencies also improve reception in buildings


Mobile Devices – Cellular Cellular wireless types:

Code Division Multiple Access (CDMA): Aging 3G standard for wireless devices used for data and

voice and is the dominant technology in the U.S. Global Systems for Mobile Communications

(GSM): Newer 3G to 3.5G wireless technology; is the dominant

technology utilized worldwide


Mobile Devices – Cellular Cellular wireless types cont’d:

Long Term Evolution (LTE): 4G or 4th generation of cellular wireless technology The next evolution of GSM; is being widely adopted Speeds currently are 2-10 times faster than 3G technology


Mobile Devices – Bluetooth

Bluetooth: Wireless standard for exchanging data over short distances in the 2400-2480 Mhz range Developed in 1994 as an alternative to data cables Must be paired with a compatible device to function Is used for data sharing and voice communications Uses low power (benefit) Examples of devices a mobile device can pair with:

Smartphone, PDA, headset, printer, keyboard, and PC


Independent / Group Work

Group Get into your groups Pick a class of mobile device (Smartphone / PDA / Tablet) Research where that device is heading with advancements in technology

and the role that wireless communication is going to play in the functionality of that mobile device

Once finished, your group will present your finding to the class Take detailed notes on each group’s research as it is being presented

Individual Pick a wireless technology (Wi-Fi / cellular / Bluetooth) Research and list some benefits of the technology over other wireless

technologies as well as some of its potential limitations


Exam Preparation

An exam will be given over the material covered in the presentation

Make sure to review your class notes and these slides

Questions will be multiple choice and true/false


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