220-1101 Mobile Devices Study Guide for the CompTIA A+ Core Series Exam

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General Information

The purpose of assessing your knowledge and skills in this area is to be sure you know how to configure and install all types of mobile devices, including, but not limited to, laptops. This does not stop after the installation and configuration are complete, however. You must also be able to ensure continued connectivity for the end-users. Approximately 15% of the questions on the CompTIA A+ Core Series 1101 test pertain to mobile device concepts. Note that approximately 75% of these questions will begin with a scenario.

Laptop Hardware and Components

You must be able to install and configure the hardware and components of a laptop in a given scenario. You should be aware of the following hardware and be comfortable replacing it.

Hardware/Device Replacement

Hardware/device replacement in laptops differs from desktop replacements. Space comes at a premium and the correct tools should be used to disassemble and reassemble laptops and their components. Be aware of the main techniques and tools used to replace laptop components. Always check manufacturer documentation before attempting hardware/device replacement.


Laptop battery chemistry is most commonly nickel-cadmium (NiCd), lithium-ion (Li-ion), nickel-metal hydride (NiMH), or lithium-polymer (Li-poly). When replacing a battery, determine if it is internal or external first. If the battery is external, remove the battery pack and replace it with a new one. If the battery is internal, remove the bottom cover, locate the battery, disconnect it from the motherboard, and remove any screws holding it in place, then remove the old battery, insert the new battery, and replace the screws and back cover.


The keyboard on a laptop is typically smaller than a traditional desktop keyboard. Laptop keyboards are located in the lower portion of the clamshell and can be either simple to remove in order to access the peripherals below or more involved and may entail removing numerous components to access the keyboard.

Random-Access Memory (RAM)

The industry-standard form factor for RAM in laptops is the small outline inline memory module (SODIMM). When replacing a SODIMM, ensure that the SODIMM is compatible with the motherboard. SODIMMs can be 200-pin DDR and DDR2, 204-pin DDR3, 260-pin DDR4, or 262-pin DDR5, and they can be 32-bit or 64-bit configurations. The RAM is located in the bottom of the clamshell.

Hard Disk Drive (HDD)/Solid State Drive (SSD) Migration

After HDD or SSD replacement, data stored on the old drive may need to be migrated to the new drive. Migration can be done either manually or through the use of migration software. Manual migration is typically preferable when only user data needs to be migrated. Before replacement, move all data to a separate location, such as the cloud or external device, and copy the data to the new drive once installed. Manual migration does not move user settings or configurations. Migration software can be used to move files, settings configurations, and applications from one drive to another. Typically, both drives need to be accessible for migration software to work.

HDD/SSD Replacement

HDDs and SSDs for laptops come in three possible form factors: 2.5”, 1.8”, or M.2. Most laptops use SSDs to save space and most laptops have a single cable connecting the drive to the laptop, providing both data and power to the drive. The drive will be located in the bottom of the clamshell. Remove the bottom cover, locate the drive, remove any screws (between one and four, typically), disconnect the SATA cable, and replace.

Wireless Cards

The wireless network interface card (NIC) allows for wireless communication between the laptop and wireless access points. The wireless NIC is located in the bottom of the clamshell. Remove the bottom cover, remove the screw holding the wireless NIC in place, disconnect the two antenna wires, and pull straight out of the M.2 socket. Replace by reversing the procedure.

Physical Privacy and Security Components

Physical privacy and security components are designed to prevent the loss of information through physical means such as shoulder surfing or theft.


Biometrics is the use of a physical body part to enhance security. Commonly used biometrics are facial recognition or a fingerprint scanner with older models. Biometrics can also be added to a laptop as a peripheral device via a USB port.

Near-Field Scanner Features

Near-field communication (NFC) is a wireless communication method that sends signals between compatible devices in close proximity, up to 10 cm, to another NFC compatible device. NFC scanners are often used for wireless payments and can be intercepted by malicious devices in close proximity. Be aware of surroundings and suspicious electronic devices when using NFC.

Mobile Device Components

Mobile device components perform the same functions as desktop components and control input and output, processing, storage, display, and connection capabilities. Note: You must be able to compare and contrast mobile device components for the exam.


There are two primary types of mobile display units: liquid crystal display and organic light-emitting diode.

Liquid Crystal Display (LCD)

LCD is a display technology that uses a current passed through a semi-crystalline liquid to produce images. The liquid crystals do not produce light and require a light source, the backlight, to display the image. Note: If a device states that it is LED, it uses LCD technology with an LED backlight. There are three popular variants of LCDs: IPS, TN, and VA, all of which use liquid crystals and transistors to form patterns in different ways.

In-plane switching (IPS)—IPS offers the widest viewing angle and the best color reproduction. Ideal for vertical mounting and those needing high-quality color, such as graphic and video artists.

Twisted nematic (TN)—As the oldest of the LCD technologies, TN has limited viewing angles and washed out or blended color reproduction. Minimal lag time makes them ideal for competitive gamers and they are an inexpensive option for office use.

Vertical alignment (VA)—VA offers the best contrast ratio of the three technologies and is a solid middle ground choice with decent color reproduction and only a slight lag.

Organic Light-Emitting Diode (OLED)

OLED displays contain both the image-producing components and the light source in a single panel. An organic light-emitting compound is sandwiched between an anode and a cathode which produces a current. The current runs through the electroluminescent compound producing light. The structure of OLEDs allows them to be flexible for curved displays. Power consumption with an OLED is less than with an LCD, and the contrast ratio is higher, producing sharper images. OLED is popular in high-end monitors and smaller devices such as smartphones.

Mobile Display Components

Besides the display unit, mobile device components contained in the top part of the clamshell include the backlight (for LCDs), the inverter (for LCDs), the screen (LCD or OLED), the digitizer (if applicable), the webcam, the microphone, and the Wi-Fi antenna.

Wi-Fi Antenna Connector/Placement

Almost all laptops today include 802.11, or wireless, functionality. The Wi-Fi antenna is generally located in the top of the clamshell case so as to place the antenna higher up for better signal reception. The antenna will be connected to the motherboard by running the wire from the top of the clamshell, through the hinge, and into the bottom of the clamshell to the motherboard.


The most common placement for a webcam or camera is in the center at the top of the clamshell above the display. Most laptops also include a built-in light next to the webcam to illuminate the user.


The microphone can be placed either next to the webcam and light in the top of the clamshell, or in the bottom of the clamshell, depending on the model of the laptop.

Touch Screen/Digitizer

A digitizer is a device that takes analog input in the form of written or drawn content, such as by a finger or stylus, and converts it into digital images. The digitizer, commonly called a touchscreen, can be built into the display as the top glass sheet or as an overlay for the display screen.


An inverter is a small circuit board located behind an LCD panel that turns DC current into the AC current which is needed by the backlight of the LCD display. Flickering screens and dimness are common signs of inverter malfunction.

Mobile Device Accessories and Ports

Mobile device accessories allow for enhanced user interaction with a mobile device and include touch pens, headsets, speakers, webcams, trackpads/drawing pads, docking stations, and port replicators. Note: You must be able to set up and configure these accessories based on given scenarios.

Connection Methods

Connection methods vary by device but may include all of the same connection methods as desktop devices.

Universal Serial Bus (USB)/USB-C/Micro USB/Mini USB

USB is the most common type of connection and can be in any USB form factor, including USB-C, micro USB, or mini USB. You should be able to identify common USB connector form factors by sight.

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A lightning connection is proprietary to Apple products and is usually the only connection type on iPhones and iPads. Macs and MacBooks can also have lightning ports for device charging.

Serial Interfaces

A serial interface is a peripheral device that is placed between two devices, such as a type of plug, that allows for data transfer serially in smaller bits between the devices. Serial interfaces include USBs, Thunderbolt, and HDMI connections. Common serial connection accessories include displays, external hard drives, and input/output devices.

Near-Field Communication (NFC)

Near-field communication (NFC) is a wireless connection type with a very short range and is primarily used in mobile commerce, RFID tags, or wireless accessories.


Bluetooth is a wireless connection method primarily used for the connection of headsets, speakers, and input devices. Bluetooth has a limited range.


A hotspot is a wireless connection type that allows for connection to the internet through a wireless access point, typically used for public connection in places such as libraries and restaurants.


Accessories for mobile devices are numerous and include input/output tools, security devices, communication enablers, and mobile commerce endpoints.

Touch Pens

A touch pen, or stylus, is a pen-shaped accessory used as a writing implement or pointing device that acts as an input device allowing for freeform writing, drawing, or clicking.


A headset is an audio input/output device that typically uses a USB or audio jack for connection. Most laptops will automatically detect and configure a headset when it is connected to the mobile device.


Speakers are audio output devices that typically connect via the USB or audio jack and typically configure automatically upon connection.


A peripheral web camera can be connected to a mobile device via a USB port and will typically configure automatically upon connection.

Docking Station

A docking station is a laptop peripheral that allows for the connection of a compatible laptop to an increased bank of expansion capabilities, including additional ports, full-sized drive bays, expansion bus slots, optical drives, and memory card slots.

Port Replicator

A port replicator is a laptop peripheral device that allows for the connection of a compatible laptop to additional ports, such as the ones found on the mobile device itself, and can be used to connect a keyboard, mouse, or printer. The port replicator allows for the continual connection of these peripheral devices, which can be used when the mobile device is connected to the port replicator.

Trackpad/Drawing Pad

A trackpad or drawing pad is often used in conjunction with a touch pen and is connected via USB. A trackpad/drawing pad is a larger version of the built-in trackpad on a laptop and offers additional features, such as on-pad menu management.


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