Mobile Devices

Week of 2026-10-13 · Download .docx

Objectives

Identify mobile connectivity technologies including Wi-Fi 6, Bluetooth, BLE, NFC, and 5G.
Describe mobile hardware including ARM SoCs, batteries, displays, and connectors.
Compare Android and iOS architectures and explain app sandboxing and MDM.
Apply mobile security practices including remote wipe, encryption, BYOD policy, and MDM.

Key terms

ARM: RISC processor architecture optimized for power efficiency, used in virtually all smartphones and tablets.
SoC: System on Chip — integrates CPU, GPU, modem, and controllers onto a single semiconductor die.
Capacitive touchscreen: Display that detects changes in electrostatic field caused by a conductive finger.
USB-C: Symmetrical universal connector for charging and data, standard on modern mobile devices.
Wi-Fi 6 (802.11ax): Wi-Fi generation using OFDMA to efficiently serve many devices simultaneously.
BLE: Bluetooth Low Energy — ultra-low power variant for IoT, wearables, and proximity beacons.
NFC: Near Field Communication — contactless technology at ~4 cm range for payments and tap-to-pair.
5G NR: Fifth Generation New Radio — cellular standard offering multi-gigabit speeds and sub-ms latency.
App sandboxing: OS isolation of each app in its own restricted environment to prevent unauthorized data access.
MDM: Mobile Device Management — software enabling IT to remotely configure, monitor, and wipe devices.
BYOD: Bring Your Own Device — policy governing use of personal devices to access corporate resources.
Remote wipe: MDM or built-in command that erases all data on a lost or stolen device over the network.
Full-device encryption: Converts all stored data to ciphertext; requires PIN/password for decryption.
Jailbreaking / Rooting: Removing OS security restrictions on iOS (jailbreak) or Android (root) — weakens security.
Factory reset: Restores device to factory state, erasing all user data and installed apps.

The concept

Mobile devices — smartphones and tablets — now outnumber traditional computers and handle tasks from email to enterprise workflows. Understanding their hardware, OS architecture, connectivity, and security is essential for modern IT support.

Mobile hardware centers on the SoC (System on Chip), which integrates the CPU, GPU, modem, image signal processor, and memory controller onto a single die — reducing size and power consumption dramatically. ARM processors use a RISC architecture optimized for performance-per-watt, enabling all-day battery life impossible with desktop x86 chips. Lithium-ion batteries last longest when kept between 20% and 80% charge — full discharge and chronic 100% charging both accelerate degradation. Capacitive touchscreens detect the electrical conductivity of a finger, which is why regular gloves do not work but conductive gloves do.

Android is built on the Linux kernel and is open-source (AOSP), allowing manufacturers to customize it. iOS is Apple-proprietary, designed exclusively for Apple's A-series silicon. Both OSes sandbox every application in an isolated environment — apps must explicitly request permissions (camera, contacts, location) and cannot read other apps' data. Android allows sideloading (installing apps from outside the official store) by toggling a setting; iOS historically restricted all installs to the App Store.

Connectivity options are extensive. Wi-Fi 6 (802.11ax) uses OFDMA to serve many devices simultaneously, critical in dense environments like schools and stadiums. Bluetooth Classic handles audio streaming; BLE uses tiny data bursts for IoT sensors and wearables, achieving years of battery life. NFC enables contactless payments (Apple Pay, Google Pay) at ~4 cm range. 5G NR delivers multi-gigabit speeds and sub-millisecond latency. Airplane Mode disables all radio transmitters simultaneously.

Mobile security requires layered controls. A 6-digit PIN provides 1,000,000 combinations versus 10,000 for a 4-digit PIN. Full-device encryption makes all stored data unreadable without the correct key. Remote wipe erases a lost device over the network. MDM enrollment gives IT the ability to enforce policies, deploy apps, and issue a remote wipe. A BYOD policy defines what personal device use is acceptable and what MDM profile must be installed. Jailbreaking or rooting removes OS security controls and dramatically increases the attack surface.

Worked examples

Example 1: A nurse's smartphone containing patient data is stolen from a hospital locker. The hospital's MDM admin immediately triggers a remote wipe through the MDM console. Within minutes of the device connecting to any network, the wipe command executes and all data is erased — the thief finds a factory-reset phone with no accessible patient information. This is why MDM enrollment is mandatory for healthcare BYOD devices.

Example 2: A school's Wi-Fi network supports 500 student devices simultaneously in a cafeteria. Students complain of slow internet. The IT team checks the access points and discovers they are older 802.11ac (Wi-Fi 5) units. Upgrading to Wi-Fi 6 access points with OFDMA allows the AP to serve multiple devices in the same channel simultaneously, dramatically improving throughput in the dense environment.

Common mistakes

Keeping a Li-ion battery at 100% charge continuously — it degrades faster; charge to 80% for daily use.
Enabling 'Install unknown apps' on Android without understanding the malware risk of unreviewed sideloaded apps.
Confusing Bluetooth Classic (audio/file transfer) with BLE (IoT/wearables) — they have different data rates and power profiles.
Treating jailbreaking as a customization feature — it removes critical OS security controls and voids warranties.
Assuming a factory reset is equivalent to remote wipe — factory reset requires physical access; remote wipe works over the network.

Self-check

Try each one before you look. A miss here costs nothing and tells you exactly what to reread.

1. Why do capacitive touchscreens not respond to regular fabric gloves?

2. Which mobile connectivity technology is best suited for IoT sensors requiring years of battery life?

3. App sandboxing on iOS and Android means:

4. What is the IT control that allows remote erasure of a lost company device?

5. What does 5G NR provide compared to 4G LTE?

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