Page 1 901 Mobile Devices Study Guide for the CompTIA® A+ exam

How to Prepare for the Mobile Devices Questions on the CompTIA A+ 901 Test

General Information

About 17% of the questions on the CompTIA A+ 901 certification test concern the operation and features of mobile devices. The most important terms and procedures are referenced in this study guide. You need to consult more detailed resources to learn all the details necessary for dealing with this type of question.

Laptop Hardware and Components

You should be familiar with the following laptop hardware and expansion components. You should also be able to explain replacement procedures of this hardware to pass your exam.

Expansion Options

Expansion options are ways to add extra capabilities to your laptop. Here are some that are commonly used:

Expresscard /34—smaller version of expansion card for laptops, 34 millimeters in size.

Expresscard /54—larger version of expansion card for laptops, 54 millimeters in size.

SODIMM—Small Outline Dual In-Line Memory Module, used for adding extra RAM.

Flash—type of non-volatile memory that can save information without needing power.

Ports/Adapters—used for mobile device connection in various circumstances. These are some types of ports and adapters: *

  • Thunderbolt: interface used for video and data, same connection type as mini DisplayPort.

  • DisplayPort: interface used for video communication, a part of VESA standard.

  • USB to RJ-45 Dongle: plugs into a USB interface to provide wired network connection.

  • USB to WiFi Dongle: plugs into a USB interface to provide wireless network connection.

  • USB to Bluetooth: plugs into a USB interface to provide Bluetooth connectivity.

  • USB Optical Drive: plugs into a USB interface to provide an external CD-ROM drive.

Hardware/Device Replacement

You should be aware of the following hardware, and be comfortable replacing it:

Keyboard—smaller sized and typically has certain keys removed or in different locations than a full-sized keyboard.

Hard Drive—These come in three main types: SSD, Hybrid, and Magnetic.

  • SSD uses flash memory for fastest response times possible.
  • Magnetic is a traditional drive that spins and reads, using specialized equipment.
  • Hybrid is a combination of both drives, and typically more cost effective than a full SSD.

SSDs come in two sizes for laptops: 1.8 in and 2.5 in.

Memory—Laptop memory typically comes in the smaller SO-DIMM and Micro-DIMM form factors.

Smart card reader—Many laptops come with this reader built in, which provides an authentication mechanism. External readers that connect via USB are also available.

Optical drive—Smaller model laptops will not include an optical drive for CD-ROMs and, instead, may use an external drive that connects via USB.

Wireless card—Most laptops include this card to allow for connecting to a wireless network. It can also be added directly to the motherboard.

Mini-PCIe—smaller and newer adapter size used for expansion options.

Screen—The screen displays are similar to desktop displays, but they will typically be smaller. Take steps to protect these screens with cases or other equipment, as they are fragile.

DC jack—Laptop chargers will come with an AC-DC power converter that is a part of the charger. This takes the AC power from the wall outlet and converts it to DC power that the laptop can use. This is plugged into the DC jack port on your laptop.

Battery—Lithium Ion is the most popular laptop battery in use today. It does degrade over time and will, eventually, need to be replaced in order to maintain a charge.

Touchpad—found on laptops to allow you to move the cursor around on the screen, similar function to a separate mouse on a desktop.

Plastics/Frames—Many laptops have durable plastic frames that are light to carry around. These are inexpensive to replace.

Speaker—Speakers are usually found integrated in the laptop. Typically, these are not of the best quality, but they do allow you to hear audio, when needed.

System board—These boards are proprietary to the laptop make and model and the replacement process is often a bit complex.

CPU—Laptop CPUs are designed to stay as cool as possible to limit the heat that builds up inside the laptop case. They may also integrate features with the CPU, such as controllers for video.

Laptop Display

You should be proficient with the details of common laptop displays to do well on this exam.


The two types of displays that you should be familiar with are LCD and OLED.

LCD—technology where light shines through liquid crystals to create images; also uses a colored filter. This type can be TN or IPS:

  • TN: Twisted Nematic LCD; fast response times.
  • IPS: plane switching LCD; good for mobile devices, but can be more expensive than TN LCD displays.

LCD technology can feature fluorescent or LED lighting:

  • Fluorescent: older technology; needs more power than backlighting.
  • LED: modern technology; useful in complex lighting designs.

OLED—uses organic diode material to create the display; no backlight.

WiFi Antenna Connector/Placement

It is important that antenna wiring be placed as high as possible to get the best signal from within your laptop case. Typically, these wires wrap around the outside edges of your display. This is also done to get the best signal possible.


Most laptops include a webcam that allows you to record audio and video. This is usually integrated into the top area, around your display.


There is also a microphone built into most laptops that allows you to record sound. This can be found in numerous locations, with some being a part of the display and others found along the edges of your keyboard.


An inverter is used with older display technology, using CCFL cold cathode fluorescent lamps. This allows your DC power to be converted into the AC power needed for these display types.


This technology allows you to be able to write directly on the display screen. This can be found mostly in devices that can act as a hybrid laptop-tablet device.