The world of USB-C is powerful and versatile, but it comes with a dizzying array of acronyms and technical terms. Understanding PD, PPS, EPR, GaN, USB4, Thunderbolt, and more is essential to choosing the right chargers, cables, and accessories to get the performance you expect from your devices. That’s where the USB-C glossary comes in. If you’ve ever felt lost trying to decode product specifications, you’re not alone.
This MTI Software USB-C glossary provides clear, concise definitions for the key terms and technologies you’ll encounter in the modern USB-C ecosystem. Use this as your quick reference guide, and follow the links for deeper dives into specific topics. Need the big picture first? See The Ultimate Guide to USB-C.
Power Delivery Standards & Features
These terms relate to how power (charging) is managed over USB-C.
USB Power Delivery (PD)
The core specification that allows for higher power transfer (beyond basic USB levels) and intelligent, two-way communication between devices and chargers over a USB-C connection. It enables faster charging for phones and the ability to power laptops. Requires PD-compatible devices, chargers, and often specific cables. Learn more: Understanding PD 3.0 vs 3.1 and PPS.
PD 3.0 (Power Delivery 3.0)
An established version of the Power Delivery standard, capable of delivering up to 100 Watts (typically 20V at 5A) using predefined voltage steps (e.g., 5V, 9V, 15V, 20V).
PD 3.1 (Power Delivery 3.1)
A major update to the PD standard, primarily introducing Extended Power Range (EPR) to deliver significantly more power.
Extended Power Range (EPR)
A key feature of PD 3.1. It allows power delivery above 100W, up to a maximum of 240W, by introducing new higher fixed voltage levels (28V, 36V, 48V) at up to 5A. Requires EPR-compatible devices, chargers, and cables. Learn more: Do You Need 100W+ USB-C Charger? and Power Up Safely: Choosing Cables Rated for 100W & 240W EPR.
Programmable Power Supply (PPS)
An optional protocol within the USB PD standard (present in PD 3.0 onwards) that allows a device to request small, real-time adjustments to both voltage and current from the charger. This optimizes charging efficiency, reduces heat generation in the device, and is required for the fastest charging speeds on certain devices (like many Samsung and Google Pixel phones). Learn more: Understanding PD 3.0 vs 3.1 and PPS.
Watt (W)
The unit of power. For charging, it indicates the rate at which energy is delivered (Volts × Amps = Watts). Higher wattage generally means faster charging potential. Learn more: Choosing the Right USB-C Charger Wattage.
Watt-hour (Wh)
The unit of energy. It represents the total amount of energy stored in a battery (like a power bank) or consumed over time (Watts × Hours = Watt-hours). It’s a better measure of total battery capacity than mAh alone. Learn more: Choosing a USB-C Power Bank: Capacity vs. Wattage.
Milliamp-hour (mAh)
A unit of electric charge commonly used to express battery capacity. While popular, it’s less precise than Wh for comparing capacity across devices with different operating voltages.
Data & Video Transfer Standards
These define how fast data or video signals travel over the USB-C connection.
USB 2.0 (High-Speed USB)
The baseline USB data standard, limited to 480 Mbps. Many basic USB-C cables (especially charging cables) only support this speed internally. Learn more: USB-C Cable Guide: Decoding Speeds.
USB 3.2 Gen 1 / Gen 2 / Gen 2×2 (SuperSpeed USB 5/10/20 Gbps)
Faster USB data transfer standards commonly found on USB-C ports and cables.
- Gen 1: 5 Gbps (Formerly USB 3.0)
- Gen 2: 10 Gbps (Formerly USB 3.1)
- Gen 2×2: 20 Gbps (Requires specific support on host, cable, and device). Learn more: USB-C Cable Guide: Decoding Speeds.
USB4
The latest major USB specification, built upon the Thunderbolt 3 protocol. It supports speeds up to 40 Gbps (though 20Gbps versions also exist), tunnels DisplayPort and PCIe data, and aims to unify previous USB standards. Requires USB4 ports and compatible cables. Learn more: Best USB4 & Thunderbolt 4 Cables.
Thunderbolt 3 (TB3)
Intel’s high-speed protocol (up to 40 Gbps) using the USB-C connector. Supports data (PCIe), video (DisplayPort), and power. Requires Thunderbolt 3 ports and cables (marked with ⚡3).
Thunderbolt 4 (TB4)
An updated Intel standard building on USB4. It mandates 40 Gbps speed, dual 4K display support (or single 8K), minimum power delivery levels, and stricter certification requirements compared to the base USB4 standard. Requires Thunderbolt 4 ports and cables (marked with ⚡4). Learn more: Best USB4 & Thunderbolt 4 Cables and Best USB-C Hubs vs. Thunderbolt 4 Docks.
DisplayPort Alt Mode (DP Alt Mode)
A VESA standard allowing a USB-C port and cable to carry native DisplayPort audio/video signals. This is how many non-Thunderbolt USB-C ports connect to external monitors. The supported DisplayPort version (e.g., 1.2, 1.4) depends on the host device. Learn more: USB-C DisplayPort Alt Mode Explained.
Cable Technology
Specific features within the cables themselves.
E-Marker Chip (Electronically Marked Cable Assembly)
An integrated circuit within a USB-C cable connector that electronically communicates the cable’s capabilities (max current, voltage, data speed, EPR support) to connected devices. Mandatory for cables supporting more than 3 Amps (i.e., >60W charging), including all 100W and 240W EPR cables. Learn more: E-Marker Chips Explained.
Active Cable
A cable (often USB4 or Thunderbolt) containing repeater/re-driver chips to regenerate the signal, allowing high speeds (like 40Gbps) over longer distances (e.g., 2 meters) than passive cables permit. Learn more: Does USB-C Cable Length Impact Speed?.
Passive Cable
A standard cable without internal signal-boosting electronics. High-speed passive cables (especially 40Gbps) are typically limited to shorter lengths (e.g., under 1 meter). Learn more: Does USB-C Cable Length Impact Speed?
Material Technology
The underlying tech in components.
GaN (Gallium Nitride)
An advanced semiconductor material used instead of traditional silicon in many modern power adapters (chargers). Its properties allow for chargers that are significantly smaller, lighter, more power-efficient, and run cooler. Learn more: What is GaN Technology?.
Conclusion
The USB-C ecosystem is powerful, but navigating the terminology can be challenging. Understanding these key terms – from power standards like PD, PPS, and EPR, to data protocols like USB4 and Thunderbolt 4, and enabling technologies like GaN and E-Markers – empowers you to make informed decisions when buying chargers, cables, hubs, and docks. Refer back to this glossary anytime you encounter an unfamiliar term, and use the linked guides for more in-depth explanations.
Explore the full USB-C world in The Ultimate Guide to USB-C.