Chapter 10: Mobile Connectivity & Application Support

A+ Core 1 — 220-1101 | Objective 1.4

Chapter 10:
Mobile Connectivity & App Support

Cellular standards, device identifiers, email protocols, Bluetooth, GPS, VPN, MDM, and mobile sync. Everything A+ 1.4 requires on mobile networks and configuration.

21 Slides Objective 1.4 Cellular • Identifiers • Email • Bluetooth • GPS • MDM Exam 220-1101

Slide 2 of 21

Cellular Standards: 3G

Third-generation mobile networking introduced true mobile data at speeds up to 7 Mbps.

GSM — Global System for Mobile

Used by AT&T and T-Mobile. SIM-based authentication. International standard — works worldwide. Phones are unlockable and carrier-swappable by replacing the SIM. GSM uses TDMA (Time Division Multiple Access) to share spectrum among callers.

CDMA — Code-Division Multiple Access

Used by Sprint and Verizon. No SIM card — device identity burned into the hardware (ESN/MEID). US only, NOT compatible abroad. Phones are carrier-locked and require carrier assistance to switch networks. Largely replaced by LTE, but still referenced on the exam.

Exam Focus: GSM vs CDMA

GSM and CDMA are not compatible with each other. International travel scenario on the exam = GSM is the correct answer. CDMA devices do not function outside the US.

3G Speed

Maximum theoretical downlink: 7 Mbps. Real-world performance was typically 1–3 Mbps. 3G introduced mobile web browsing, app stores, and GPS navigation as viable use cases.

Slide 3 of 21

Cellular Standards: 4G / LTE

Fourth-generation networks moved from circuit-switched to fully IP-based communication.

LTE — Long Term Evolution

The dominant 4G technology. IP-based end-to-end. Downlink: 100 Mbps for high-mobility users (vehicles, trains). Up to 1 Gbps for stationary or low-mobility users. LTE replaced both GSM and CDMA voice infrastructure with VoLTE (Voice over LTE).

WiMAX

Competing 4G standard (IEEE 802.16). Faster theoretical speeds than early LTE, but limited carrier adoption. Sprint deployed WiMAX briefly before switching to LTE. Rarely deployed today but still referenced in the A+ objectives as an alternative 4G technology.

IP-Based Architecture

Unlike 3G circuit-switched voice, 4G treats all communication (voice and data) as IP packets. This enables lower latency, better spectrum efficiency, and easier integration with internet services. All calls on 4G networks use VoLTE or similar VoIP technology.

Speed Summary

3G: up to 7 Mbps • 4G high-mobility: 100 Mbps • 4G stationary: up to 1 Gbps

Slide 4 of 21

Cellular Standards: 5G

Announced 2016, deployed 2019. Sustained speeds over 1 Gbps, theoretical max 20 Gbps.

5G Category	Full Name	Primary Use Case
eMBB	Enhanced Mobile Broadband	Smartphones, consumer mobile data, streaming
URLLC	Ultra-Reliable Low-Latency Communications	Autonomous vehicles, remote surgery, industrial automation
mMTC	Massive Machine Type Communications	IoT sensors, smart city infrastructure, meter reading

Speed Progression

3G: 7 Mbps → 4G: 100 Mbps–1 Gbps → 5G: 1+ Gbps sustained / 20 Gbps theoretical. Each generation represents roughly a 10–20x improvement in peak throughput.

5G Frequency Bands

Low-band (sub-1 GHz): wide coverage, moderate speed. Mid-band (1–6 GHz): balance of coverage and speed. mmWave (24–100 GHz): extreme speed, very short range — requires dense small-cell deployments, blocked by walls and rain.

Slide 5 of 21

Hotspots & Tethering

Sharing a cellular data connection with other devices.

Mobile Hotspot

The mobile device broadcasts a Wi-Fi network. Other devices connect to it wirelessly and share the phone's cellular data connection. Controlled via Settings. Data counts against the device's cellular plan. Carrier may charge extra or throttle hotspot traffic.

USB Tethering

Share the cellular connection via a USB cable between the phone and a laptop. The laptop sees the phone as a network adapter. More reliable than Wi-Fi hotspot for stationary use. Simultaneously charges the phone while tethering. Requires phone USB drivers on Windows.

Bluetooth Tethering

Share the cellular connection over a Bluetooth PAN (Personal Area Network). Lower throughput than Wi-Fi or USB due to Bluetooth bandwidth limits. Shorter range. Less battery drain than Wi-Fi hotspot. Useful as a fallback when Wi-Fi hotspot is unavailable.

MiFi Device

A dedicated mobile hotspot device (e.g., Verizon MiFi, Netgear Nighthawk M) with its own cellular SIM. Supports multiple simultaneous Wi-Fi clients. Better battery life and signal than phone tethering. Used in enterprise field deployments and remote work environments.

Slide 6 of 21

Cellular Firmware Updates

Four update types that maintain a device's wireless connectivity and carrier configuration.

Update	Full Name	What It Controls
Baseband OS	Baseband Operating System	All wireless communications on the device (cellular, GPS, Bluetooth)
SIM OS	SIM Card Operating System	Data transfer between the phone and the SIM chip; authentication with carrier
PRI	Product Release Instruction	Carrier-specific configuration settings (network parameters, APN, roaming settings)
PRL	Preferred Roaming List	Directs the phone to connect to the correct tower when outside the home carrier area

Exam Focus: PRL

The Preferred Roaming List (PRL) is frequently tested. If a device is failing to connect to towers while roaming, updating the PRL resolves it. PRL is a CDMA-era term but still appears in A+ questions.

Slide 7 of 21

Mobile Device Identifiers

Five unique IDs used for hardware tracking, network auth, and secure payments.

Acronym	Full Name	Digits	Identifies
IMEI	International Mobile Equipment Identity	15	The physical phone hardware; used to block stolen devices
MEID	Mobile Equipment Identifier	14	Same purpose as IMEI; matches first 14 digits of IMEI; used on CDMA devices
IMSI	International Mobile Subscriber Identity	15 (on SIM)	The subscriber and their network; stored on the SIM card
ICCID	Integrated Circuit Card Identifier	19–20 (on SIM)	The SIM card itself; global SIM serial number
SEID	Secure Element Identifier	Hex code	Secure applications: NFC payments, Apple Pay, digital wallets

Key Distinction: Phone vs. SIM

IMEI identifies the physical phone. IMSI and ICCID are stored on the SIM card and identify the subscriber and SIM respectively. Swap the SIM = new IMSI/ICCID. The IMEI stays with the hardware forever.

Slide 8 of 21

IMSI Structure

The 15-digit IMSI encodes country, carrier, and subscriber identity in three segments.

MCC — Mobile Country Code

3 digits. Identifies the country of the home network. United States: 310 or 311. United Kingdom: 234. Japan: 440. Assigned by the ITU (International Telecommunication Union). First 3 digits of every IMSI.

MNC — Mobile Network Code

2–3 digits. Identifies the carrier within that country. US examples: AT&T = 410, T-Mobile = 260, Verizon = 480. Combined with MCC, uniquely identifies the home network worldwide. Used for roaming agreements between carriers.

MSIN — Mobile Station ID Number

Up to 10 digits. Sequential serial number assigned by the carrier to identify the individual subscriber within the network. The MSIN is what changes when a subscriber ports their number to a new carrier while keeping the same physical SIM.

A technician receives a stolen-phone report. They obtain the IMEI from the box and report it to the carrier, which blacklists it. The thief swaps SIMs (changing IMSI/ICCID) but the phone still cannot connect — because the IMEI is hardware-bound and carrier-blocked. Understanding IMEI vs. IMSI is critical for device security scenarios.

Slide 9 of 21

Wi-Fi & VPN Configuration

Connecting mobile devices to wireless networks and encrypted corporate tunnels.

Wi-Fi Connection Steps

1. Settings → Wi-Fi → Enable
2. Select network from available list
3. Enter passphrase if required
4. Verify connection (IP assigned)
Hidden SSID: manually enter network name, security type, and password.

VPN Purpose

Creates an encrypted tunnel from the mobile device to a corporate or remote network. Required for accessing internal resources over public Wi-Fi or cellular. Configured under Settings → VPN. Requires: server address, protocol, username, and password (or certificate).

VPN Protocol	iOS	Android	Notes
IKEv2	Yes	Yes	Current standard, fast reconnection, widely supported
IPsec	Yes	Yes	Layer 3 encryption; often paired with IKEv2 or L2TP
L2TP	Yes	Yes	Older; typically used with IPsec for encryption
PPTP	No	Yes	Deprecated, weak security; Android only — exam-tested

Critical Exam Point

PPTP is available on Android but NOT on iOS. Server and client must use the same VPN protocol. If protocols do not match, the connection fails. PPTP is considered insecure by modern standards but still appears on the A+ exam.

Slide 10 of 21

Bluetooth Pairing

Short-range wireless peripheral connectivity — five steps from power-on to working device.

Step 1: Enable & Enter Pairing Mode

Power on the Bluetooth peripheral. Enable pairing/discoverable mode — typically by holding a button for 3–5 seconds until an LED flashes. Without pairing mode, the device is invisible to other Bluetooth devices.

Steps 2–3: Locate & Enter PIN

On the mobile device: Settings → Bluetooth → scan for devices. Select the peripheral from the list. Enter the PIN or passkey if prompted — commonly 0000, 1234, or a code displayed on the device screen.

Steps 4–5: Confirm & Test

Confirm the pairing on the peripheral (press a button combination if required). Once paired, test functionality — audio playback, keyboard input, or whatever the device provides. Paired devices reconnect automatically in the future.

Mnemonic: TEPCT

Turn on → Enable pairing mode → PIN code → Confirm pairing → Test connectivity. Pairing mode = discoverable mode. Without it, scanning will not find the device.

Slide 11 of 21

Location Services: GPS & GNSS

Multiple satellite constellations provide positioning; 4 satellites required for 3D fix.

System	Country / Organization	Satellites	Accuracy
GPS	United States (DoD)	24	3–5 m (SPS) / <1 m (PPS)
GLONASS	Russia	24	~5 m
Galileo	European Space Agency	30	<1 m (commercial)
BeiDou (BDS)	China	35	1.5–2.5 m
IRNSS	India	7	<20 m (regional)

US GPS Service Tiers

SPS (Standard Positioning Service): free, open, civilian use worldwide.
PPS (Precise Positioning Service): encrypted, requires DoD authorization, military and government only. Significantly higher accuracy than SPS.

4-Satellite Requirement

A GPS receiver needs signals from at least 4 satellites for a 3D position fix (latitude, longitude, altitude). 3 satellites provide 2D only. Modern phones use multi-constellation receivers (GPS + GLONASS + Galileo) for faster fixes and better urban coverage.

Slide 12 of 21

Airplane Mode & Cellular Data

Controlling wireless radios at the device level.

Airplane Mode

Disables all wireless transmissions simultaneously: cellular radio, Wi-Fi, Bluetooth, and NFC. Required by aviation regulations during takeoff and landing. Individual radios (Wi-Fi, Bluetooth) can be re-enabled while airplane mode remains on. GPS (receive-only) is not transmitting and may function in airplane mode depending on the device.

Disabling Cellular Data

Settings → Cellular (iOS) or Settings → Network & Internet (Android). Disables data only; voice and SMS calls still function on cellular. Use cases: avoid roaming charges while traveling internationally, conserve battery, force device to use Wi-Fi only, troubleshoot connectivity issues.

Cellular Location Fallback

When GPS signal is unavailable (indoors, urban canyons), devices use cellular tower triangulation for approximate location. Three towers = triangulated position. Less accurate than GPS (tens to hundreds of meters vs. 3–5 m), but works without a clear sky view.

Roaming

When outside the home carrier coverage area, the device connects to a partner carrier network. Data and voice rates may be significantly higher. Carriers push PRL updates to manage which partner towers are preferred. International roaming requires a GSM device with an unlocked SIM slot.

Slide 13 of 21

MDM: Mobile Device Management

Server-based platform that manages the entire device — enrollment through remote wipe.

Enrollment & Configuration

Devices are enrolled into the MDM server (e.g., Microsoft Intune, Jamf, MobileIron). MDM pushes security policies: PIN/password requirements, screen lock timeout, encryption enforcement, Wi-Fi and VPN profiles, and camera disable. Enrollment can be user-initiated or zero-touch (factory-provisioned).

Monitoring & Tracking

MDM can report real-time device location, app inventory, OS version, compliance status, and last check-in time. Administrators can detect jailbroken or rooted devices, outdated OS versions, and unauthorized app installations. All monitoring requires device enrollment and user consent.

Remote Actions

Remotely: lock the device, reset the PIN, trigger a full remote wipe (factory reset), or selective wipe (corporate data only). Remote wipe is critical for lost or stolen devices containing sensitive data. Actions are queued and executed when the device next connects to the internet.

MDM Scope

MDM controls the entire device — hardware, OS, apps, and data. It can lock out the user completely and wipe all personal data, not just corporate content. This scope makes MDM appropriate for corporate-owned devices but intrusive on personal BYOD devices.

Slide 14 of 21

MAM & BYOD

Mobile Application Management controls only apps — leaving personal data untouched.

MAM Capabilities

Remotely install corporate apps, delete apps and their data, encrypt app-level data, specify allowed apps (whitelist), block prohibited apps (blacklist), and wipe app data without wiping the entire device. The personal photos, texts, and personal apps on the device are not managed or visible to the administrator.

MDM vs. MAM

MDM: controls the whole device — lock, full wipe, OS enforcement, hardware settings. MAM: controls only applications — install, remove, data wipe of work apps only. MDM is for corporate-owned hardware. MAM is the appropriate choice when employees use personal devices (BYOD).

BYOD Scenario

An employee leaves the company. With MAM, the administrator wipes the corporate email app, Salesforce app, and related data from the personal phone. The employee keeps their personal photos, contacts, and apps untouched. With MDM, a full wipe would erase everything — unacceptable for personal devices.

ActiveSync

Microsoft Exchange's protocol for pushing email, calendar, and contacts to mobile devices. Administrators can use ActiveSync policies to enforce PIN requirements, screen lock timeout, and remote wipe from the Exchange admin console, without deploying full MDM.

Slide 15 of 21

Email Protocols & Ports

SMTP sends. POP3 and IMAP receive. Port numbers are heavily tested on the exam.

Protocol	Purpose	Default Port	Secure Port
SMTP	Send mail (outbound push)	25	465 (SSL) / 587 (STARTTLS)
POP3	Retrieve mail — downloads and typically deletes from server	110	995
IMAP	Retrieve mail — syncs across multiple devices, keeps on server	143	993

POP3 vs IMAP

POP3 downloads mail to one device and removes it from the server by default. Good for single-device access. IMAP syncs mail state across all devices — read on phone, marked read on laptop. If the exam asks which protocol to use for multi-device access, the answer is IMAP.

Port Memory Aid

SMTP = 25 • POP = 110 • IMAP = 143
Secure versions swap to 9xx: POP secure = 995, IMAP secure = 993.
SMTP secure = 465 (SSL) or 587 (TLS submission). The 587 port is the modern standard for client-to-server mail submission.

Slide 16 of 21

Mobile Synchronization

Data types that sync and the platform methods used for iOS and Android.

Communication Data

Contacts, email, calendar events, and tasks. These sync bidirectionally between the mobile device and the cloud or exchange server. Changes on one device propagate to all synced devices within seconds when connected to the internet.

Media & Documents

Photos, videos, music, documents, and bookmarks. Typically synced to cloud storage (iCloud Photos, Google Photos). Large media files are the primary cause of data cap overages during sync — configure to sync over Wi-Fi only.

Application Data

App data, passwords, settings, social media feeds, and location history. Apps sync their own data via their respective cloud backends. Password sync (iCloud Keychain, Google Password Manager) requires explicit permission and device authentication.

Platform	Local Sync	Cloud Sync
iOS	Finder (macOS) / iTunes (Windows)	iCloud — email, contacts, calendar, photos, backup
Android	Manufacturer tools (Samsung Smart Switch, etc.)	Google Drive — contacts, calendar, photos, backup

Slide 17 of 21

Email Providers & Mobile Config

Common providers and the settings required to manually configure a mobile email account.

Common Providers

iCloud — Apple accounts; uses IMAP on port 993
Gmail — Google; IMAP 993, SMTP 587
Exchange Online — Microsoft 365; uses ActiveSync or IMAP
Yahoo Mail — IMAP 993, SMTP 465
Most providers auto-configure on modern devices; manual configuration needed for custom/corporate domains.

Manual Config Requirements

Incoming server: hostname, port, security type (SSL/TLS)
Outgoing server: hostname, port, authentication required (yes/no)
Username: usually the full email address
Password: email account password or app-specific password (if 2FA enabled)
Domain: required for Exchange/ActiveSync accounts

Data Cap Warning

Syncing large data sets (photos, video attachments) over cellular consumes significant data. Configure sync to occur over Wi-Fi only to avoid overage charges. ActiveSync has a setting to limit email attachment size fetched over cellular.

Slide 18 of 21

Exam Practice: Quick Questions

Six A+ style scenario questions — answers in gold. Cover them first.

Q1

A user traveling internationally cannot make calls on their Verizon phone. Which 3G technology is most likely the cause? — CDMA. Verizon used CDMA which is US-only. GSM works internationally; CDMA does not.

Q2

A stolen phone has its SIM replaced. The new owner still cannot connect to any carrier. Why? — The IMEI (hardware identifier) was blacklisted. Replacing the SIM changes IMSI/ICCID but not the IMEI.

Q3

A technician sets up a VPN on a user's iPhone. Which protocol is NOT available as a native option? — PPTP. iOS removed PPTP support. Android still includes it. IKEv2, IPsec, and L2TP are available on both.

Q4

A user accesses work email from a phone, tablet, and laptop. Which email protocol keeps all devices in sync? — IMAP. It syncs mail state across all devices and keeps messages on the server. POP3 is single-device only.

Q5

An employee leaves the company. HR wants only corporate app data removed from their personal phone. Which solution is used? — MAM (Mobile Application Management). MAM performs selective app wipe without touching personal data.

Q6

A device roaming on a partner network keeps connecting to distant towers instead of the closest. What should be updated? — PRL (Preferred Roaming List). Updating the PRL directs the device to the optimal tower when roaming.

Slide 19 of 21

Exam Practice: Port Drill

Email ports appear on nearly every practice exam. Lock these in.

Protocol	Port	Direction	Security
SMTP	25	Outbound (send)	Unencrypted relay
SMTP SSL	465	Outbound (send)	SSL/TLS
SMTP TLS	587	Outbound (submit)	STARTTLS (modern standard)
POP3	110	Inbound (retrieve)	Unencrypted
POP3 SSL	995	Inbound (retrieve)	SSL/TLS
IMAP	143	Inbound (sync)	Unencrypted
IMAP SSL	993	Inbound (sync)	SSL/TLS

Quick Pattern

Secure ports follow a pattern: POP secure = 995 (110 + 885), IMAP secure = 993 (143 + 850). Both start with 9. SMTP adds a second secure port at 587 for submission (client to mail server).

Common Wrong Answer

Do not confuse SMTP 25 with SMTP 587. Port 25 is server-to-server relay and is blocked by most ISPs. Port 587 is the client submission port and is what mobile email clients use. Port 465 is the legacy SSL option still used by some providers.

Slide 20 of 21

Key Vocabulary

Chapter 10 terms organized by category.

Cellular & Connectivity

GSM — SIM-based, international (AT&T, T-Mobile)
CDMA — hardware ID-based, US only (Verizon, Sprint)
LTE — 4G standard, IP-based, up to 1 Gbps
eMBB / URLLC / mMTC — 5G use case categories
PRL — Preferred Roaming List (tower preference)
Baseband OS — firmware controlling all wireless radios

Identifiers

IMEI — 15-digit hardware ID (the phone)
MEID — 14-digit hardware ID (CDMA variant)
IMSI — 15-digit subscriber ID (on SIM)
ICCID — SIM card serial number (19–20 digits)
SEID — Secure Element ID (NFC payments)
MCC / MNC / MSIN — IMSI component breakdown

Management & Email

MDM — Mobile Device Management (whole device)
MAM — Mobile Application Management (apps only)
BYOD — Bring Your Own Device (use MAM, not MDM)
ActiveSync — Exchange push protocol for mobile
SMTP / POP3 / IMAP — email protocols
PPTP — VPN protocol; Android only, not iOS

Slide 21 of 21 — Chapter 10 Complete

Chapter 10 Summary

Eight key takeaways from Mobile Connectivity & Application Support.

1

GSM vs. CDMA: GSM is SIM-based and works internationally. CDMA is US-only and hardware-locked. International travel question = GSM.

2

Speed progression: 3G = 7 Mbps. 4G = 100 Mbps–1 Gbps. 5G = 1+ Gbps sustained, 20 Gbps theoretical. Each generation fully IP-based from 4G onward.

3

IMEI vs. IMSI: IMEI identifies the physical phone (hardware). IMSI and ICCID identify the subscriber and SIM card. Blacklisting IMEI survives SIM swaps.

4

PPTP: Available on Android, NOT on iOS. All other modern VPN protocols (IKEv2, IPsec, L2TP) are available on both platforms. VPN server and client must match.

5

MDM vs. MAM: MDM controls the whole device. MAM controls apps only. BYOD environments should use MAM to avoid wiping personal data.

6

Email ports: SMTP 25 / 465 / 587. POP3 110 / 995. IMAP 143 / 993. Multi-device access = IMAP. Server-side retention = IMAP. Single device = POP3.

7

GPS: Needs 4 satellites for 3D fix. US GPS has SPS (free) and PPS (DoD military). Modern phones use multi-constellation (GPS + GLONASS + Galileo) for better coverage.

8

Bluetooth pairing: Enable pairing mode, scan, enter PIN, confirm, test (TEPCT). PRL updates fix roaming tower selection. Baseband OS controls all wireless radios.