3 things to watch out for when choosing a USB-C adapter or cable

USB Type-C, or USB-C, is the latest standard that is slowly replacing the USB Type-A ports that have been so prevalent in our computing devices over the past two decades.


Left: USB-C, the new standard with a small, reversible connector
Right: USB-A:, the old standard with a larger, non-reversible connector

Thanks to its impressive bandwidth (up to 10 Gbps) a USB-C port is truly universal: bundling high speed data, video, and power all in a single cable. This gives manufacturers flexibility in designing devices that are thinner and lighter, while also improving usability by reducing the number of cables connected to your computer.



The USB-C standard combines the functionality of several cables into one.

However, since the USB-C standard is so new, there are many non-compliant products that have been rushed to market. These devices have not been certified by the USB-IF and may cause compatibility issues and even potentially damage your device.

Here are the three most important things watch out for when choosing a USB-C adapter or cable.

1. Correct connector dimensions


Compliant USB-C adapter compared to a bulkier, non-compliant adapter

2. Safe resistor values

This one is a bit technical but still very important. Many non-compliant USB Type-C to USB Type-A cables or adapters incorrectly terminate the Configuration Channel with a 10kΩ pull-up resistor to VBUS instead of a 56kΩ pull-up, which is mandated by the USB-C specification. When charging a USB-C device with a legacy USB Type-A charger, this can cause the connected device to draw too much power. As such, there have been many reported incidences of laptops (from Google, Apple, and others) that have been damaged by non-compliant adapters or cables sending too much power. To avoid this issue, only purchase USB-C products that have been certified by the USB-IF.


How a 56K resistor protects your device vs. a 10K resistor

3. Accurate pin pitch

There are 24 pins on a female USB-C port and 22 pins on the male USB-C connector. These pins are packed in a very small form factor with a “pitch” (the distance between the pins) of only 0.25 mm. The use of precision machinery and premium materials is required to ensure reliable pin contact and that no corrosion will occur over time. Any shorts or an impedance mismatch due to poor pin contact may result in damage to your electronics. If you’re experiencing performance issues then inspect the pin pitch right away to see if there are any irregularities or areas where contact might be inconsistent.


Correct pin pitch according to the USB-C specification.

Learn more about Moshi’s complete range of certified USB-C products here. If you would like also learn more about the USB-C interface, check out our 5 Things to Know About the USB-C Interface post.

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