Mixed Deck — All CMT Topics Flashcards

Which component in a mobile device is responsible for wireless communication?

Answer: Wireless communication module

The wireless communication module is the dedicated component within a mobile device responsible for enabling various forms of wireless connectivity. This module integrates technologies such as Wi-Fi, Bluetooth, and cellular (2G/3G/4G/5G) radios, allowing the device to connect to networks, access the internet, and communicate with other devices without physical cables. It is essential for all modern mobile connectivity features.

Which wireless standard allows a mobile device to make contactless payments at a point-of-sale terminal?

Answer: NFC (Near Field Communication)

NFC operates at 13.56 MHz over distances under 4 cm and is the standard used by Apple Pay, Google Pay, and other mobile payment systems.

A smartphone powers on but the touchscreen is completely unresponsive after a drop. The display shows the home screen correctly. What is the most likely cause?

Answer: Digitizer layer damage or disconnected digitizer cable

A drop can crack or disconnect the digitizer (touch sensor layer) while leaving the display itself functional.

What is the primary purpose of maintaining detailed repair logs for each device serviced?

Answer: To provide an audit trail, support warranty claims, ensure quality control, and protect against liability

Comprehensive repair logs are essential for resolving disputes, supporting warranties, and demonstrating professional due diligence.

A customer's Android device is showing signs of a rogue profile installed via a phishing link. What is the FIRST step a technician should take?

Answer: Navigate to device admin settings and revoke the rogue profile's permissions before removal

Rogue device admin profiles must first be deactivated in settings before they can be removed, as active admin profiles block their own deletion.

What does 'Pass-Through Charging' mean in the context of power banks and mobile devices?

Answer: Simultaneously charging the power bank while it charges a connected device

Pass-through charging allows a power bank to receive charge from an input source while simultaneously outputting power to charge a connected device.

A repair technician replaces a battery and notices the device's IMEI sticker is removed. Why is this a significant concern?

Answer: The device may be stolen, as IMEI removal is a common tactic to obscure device identity

IMEI numbers uniquely identify mobile devices and their removal is commonly associated with stolen devices whose owners have blacklisted the IMEI.

A customer traveling internationally reports their US phone shows 'No Service' in Europe. After confirming the phone is unlocked, what should the technician check next?

Answer: Whether the phone supports the frequency bands used by European carriers (e.g., 900/1800 MHz GSM, B3/B7 LTE)

Even an unlocked phone won't work internationally if its radio hardware doesn't support the frequency bands used by local carriers in that country.

When should a technician recommend a factory reset as a repair solution?

Answer: After all other software troubleshooting steps have failed and data has been backed up

A factory reset is a last resort for software issues because it destroys all user data.

What is Bluetooth technology used for in mobile devices?

Answer: To wirelessly connect to peripherals

Bluetooth is a short-range wireless technology used in mobile devices to establish connections with various peripheral devices without the need for physical cables. This includes connecting to wireless headphones, speakers, smartwatches, car infotainment systems, and other accessories. It enables convenient, low-power data exchange for a wide range of personal area network applications, enhancing the device's functionality and user experience.

A phone's screen flickers only when the battery is below 20%. Which scenario best explains this?

Answer: Insufficient voltage at low battery causes display driver instability

As battery voltage drops under load, the display driver IC may receive insufficient power, causing visible flickering before auto-shutdown triggers.

When disposing of a mobile device on behalf of a customer, which step is MOST critical to ensure data protection compliance?

Answer: Perform a factory reset and verify data destruction

A factory reset followed by verification ensures all user data is wiped; simply removing accounts or apps does not fully protect against data recovery.

A technician is replacing the battery on a modern iPhone that uses 'True Tone.' What must be done to restore True Tone functionality after the repair?

Answer: Re-pair the display using Apple's System Configuration tool

True Tone data is stored in the display module's EEPROM and must be re-paired to the logic board using Apple's proprietary System Configuration tool or third-party equivalents.

A customer reports their phone's GPS is inaccurate indoors but works perfectly outdoors. What is the most appropriate response?

Answer: Explain that GPS requires clear line of sight to satellites and works as intended

GPS signals are significantly attenuated by building materials, making indoor GPS inherently inaccurate—this is normal device behavior, not a defect.

A technician is asked to image a customer's device before repair. Where is the SAFEST place to store a temporary device image?

Answer: On an encrypted, password-protected local drive dedicated to customer data

Encrypted, access-controlled dedicated storage ensures customer data is protected from unauthorized access during the repair window.

A phone's speaker produces distorted audio at all volume levels but earpiece audio is clear. Which component should you replace?

Answer: Loudspeaker/bottom speaker assembly

Distortion across all volumes while earpiece remains clear isolates the fault to the loudspeaker unit itself.

A customer becomes verbally aggressive. The CMT-recommended response is to:

Answer: Stay calm, maintain a professional tone, and offer to involve a manager if needed

Remaining professional and offering escalation options protects staff and often resolves conflicts.

A customer's phone consistently overheats when using a particular case. What is the most likely cause?

Answer: The case insulates the device and traps heat generated during processing or charging, preventing normal thermal dissipation

Smartphones rely on convective heat loss through the chassis; poorly ventilated cases reduce thermal dissipation.

What is the purpose of an OTG (On-The-Go) adapter for Android devices?

Answer: It allows the phone to act as a USB host, enabling connection of flash drives, keyboards, and other USB peripherals

USB OTG mode switches the device from USB peripheral to USB host, enabling direct peripheral connection.

Which of the following BEST prevents unauthorized SIM swapping that could compromise mobile account security?

Answer: Enabling carrier account PINs and SIM lock features

A carrier account PIN adds authentication before any SIM changes can be made, blocking attackers from porting a victim's number to their own SIM.