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Difficulty: HardMobile Device Ports and Accessories

A field technician is deploying mobile handheld terminals to warehouse workers who must connect a wired USB Type-A barcode scanner while simultaneously powering the terminal. When using a passive USB Type-C hub powered only by the mobile terminal, the terminal charges slowly from an external power supply connected to the hub, but it fails to detect the barcode scanner. Which of the following best explains why the barcode scanner is not functioning, and what is the appropriate solution?

  1. The passive hub does not properly facilitate Configuration Channel (CC) signaling for Dual-Role Data (DRD) and USB Power Delivery negotiation; deploying a powered USB-C dock with explicit host-mode peripheral support is required.Answer
  2. B
    Mobile device USB Type-C ports require active Thunderbolt protocol controllers to negotiate host data connections while receiving external power, necessitating a Thunderbolt 4 docking station.
  3. C
    Mobile Application Management (MAM) policies automatically block USB data transfer whenever an external power source is detected; modifying the MAM security policy to allow USB debugging will enable the scanner.
  4. D
    The mobile terminal must have Exchange ActiveSync enabled to establish a background synchronization bridge for attached USB host peripherals.

Answer

The passive hub fails to negotiate Configuration Channel (CC) pin signaling required for simultaneous USB Power Delivery and Dual-Role Data host mode operations. The technician must deploy a powered USB-C dock designed to support host-mode peripheral data transfer while delivering power.
USB Type-C relies on Configuration Channel (CC) pins within the physical connector to negotiate roles such as host vs. device (Dual-Role Data) and power provider vs. consumer (USB Power Delivery). A simple passive hub often lacks the active management circuitry necessary to negotiate charging the terminal while simultaneously maintaining the terminal's USB host controller state required to operate external peripherals like barcode scanners. Replacing the passive hub with a powered USB-C dock ensures proper CC signaling and power delivery.

Step-by-Step Solution

1
Analyze the technical requirements of the scenario.
The mobile terminal needs to act as a USB host (to receive barcode data from the USB Type-A scanner) while simultaneously acting as a power sink (receiving charge from an external supply).
USB Type-C supports Dual-Role Data (DRD) and Dual-Role Power (DRP) controlled dynamically through Configuration Channel (CC) logic pins.
2
Diagnose the hardware failure cause.
Passive hubs frequently lack dedicated controller logic to pass CC pin negotiation state transitions for both USB Power Delivery (USB PD) and host-mode peripheral enumeration under simultaneous charge scenarios.
Without proper CC pin role signaling, the handheld terminal defaults to a power-receiving peripheral state and disables host controller power/data routing to connected Type-A ports.
3
Identify the proper hardware solution.
Deploying a powered USB-C dock or port replicator with dedicated controller logic handles USB PD and host role negotiation correctly.
A dedicated dock actively signals the mobile device to operate as a data host while safely receiving power.

Key Concept

USB Type-C Configuration Channel (CC) signaling and Dual-Role Data / Power Delivery capabilities for mobile accessories.
Estimated Time:1m 30s
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Topics

Mobile Device Ports and Accessories

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