Ports and Peripherals

I/O, Expansion, and Power Connectivity

A guide to the external ports, peripherals, and expansion options for mobile devices, including docking stations, port replicators, and charging standards.
Author

Chuck Nelson

Published

November 16, 2025

1 Purpose

While the internal components of mobile devices are highly integrated, their utility is defined by how they connect to the outside world. This document covers the external hardware components that enable connectivity and expansion, from physical I/O ports to docking stations. We will also briefly review the power connectors that charge the device’s battery, a topic that will be explored in greater detail later.

2 What You’ll Accomplish

By the end of this reading, you will be able to:

  • Identify common I/O ports found on laptops and other mobile devices (e.g., USB-C, Thunderbolt, HDMI).
  • Differentiate between a docking station and a port replicator.
  • Recognize the common charging ports used on modern mobile devices (USB-C, Lightning).

This reading maps to the following program and course learning outcomes:

  • Course Learning Outcomes (CLOs):
    • 1. Identify hardware and basic network components: This document focuses on the physical ports and peripherals used to connect mobile devices.

This exercise develops the following skills, which align with the O*NET SOC Code 15-1232.00 for Computer User Support Specialists.

Learning Objective O*NET KSAs Technologies Used
Identify common I/O ports on mobile devices. Knowledge: Computers & Electronics, Telecommunications
Skills: None		 USB-C, Thunderbolt, HDMI
Differentiate docking stations & port replicators. Knowledge: Computers & Electronics
Abilities: Information Ordering		 Docking Station, Port Replicator
Recognize modern charging standards. Knowledge: Computers & Electronics
Abilities: None		 USB-C PD, Lightning

3 Common I/O Ports

Laptops and, to a lesser extent, tablets offer a variety of ports for connecting peripherals.

  • USB-A: The classic rectangular USB port. Still common for connecting mice, keyboards, and older peripherals.
  • USB-C: The modern, oval-shaped, reversible USB port. It’s a versatile standard that can handle data transfer, video output, and power delivery in a single cable.
  • Thunderbolt: A high-performance standard developed by Intel and Apple that uses the USB-C connector. A Thunderbolt port can do everything a USB-C port can do, but at much higher speeds (typically 40 Gbps). It can drive multiple high-resolution displays and connect to high-speed external storage or docking stations.
  • HDMI/DisplayPort: Dedicated ports for connecting external monitors. While USB-C and Thunderbolt can also carry video, these dedicated ports are still common.
  • SD/MicroSD Card Reader: Allows for easy transfer of photos and videos from a camera.
  • 3.5mm Audio Jack: The standard port for connecting wired headphones and microphones.
  • RJ45 Ethernet: A dedicated port for a wired network connection, offering more speed and reliability than Wi-Fi. Common on business laptops, but often omitted on thin-and-light models.

4 Expansion: Docking Stations vs. Port Replicators

For users who frequently switch between a mobile and a desk setup, docks and port replicators are essential.

  • Port Replicator: A simple device, often a small dongle or hub, that plugs into a single port on your laptop (usually USB-C) and provides several other ports (e.g., USB-A, HDMI, SD card reader). They are portable and generic.
  • Docking Station: A more robust, stationary device that a laptop “docks” into. True docking stations often use a proprietary physical connector or a high-speed Thunderbolt connection. They provide power to the laptop and connect it to multiple monitors, a full-sized keyboard, a mouse, and a wired network—all with a single connection. This allows for a seamless transition from a portable laptop to a full desktop experience.

5 Charging and Power Ports

Virtually all modern mobile devices have standardized on one of three connector types for charging. While we will cover battery technology in detail in a later document, it’s important to recognize the physical ports.

  • USB-C: The universal standard for modern Android phones, tablets, and nearly all new laptops. Its key feature is Power Delivery (PD), a standard that allows devices to negotiate for higher wattage, enabling fast charging of even large devices like laptops.
  • Lightning: Apple’s proprietary connector used on iPhones and some iPad models.
  • Micro-USB: The older standard for Android phones and other small electronics. It is less robust than USB-C and is being phased out.

6 Reflect and Review

ImportantReflection: 3-2-1

Now that you have reviewed this document, take a moment to reflect on your learning in your Microsoft Teams Student Notebook:

  • 3 different types of ports you might find on a modern laptop.
  • 2 key differences between a port replicator and a docking station.
  • 1 question you still have about the Thunderbolt standard.
TipCheck on Learning

Answer these questions in your notebook to solidify your understanding:

  1. You need to connect your laptop to two external monitors, a wired network, a keyboard, and a mouse, and also have it charge, all by plugging in a single cable. What type of device would you need?
  2. What is the main advantage of the USB-C connector over older USB-A connectors?
  3. You have a new laptop that only has USB-C ports, but your favorite mouse uses a USB-A connector. What is the simplest device you could use to connect your mouse?
  4. What is the name of Apple’s proprietary charging port for iPhones?
  5. A port on your laptop has a small lightning bolt symbol next to it. What does this likely indicate?
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