USB has Become the Mainstream Interface with “Plug and Play”

Since USB came out, its popularity has increased due to its plug-and-play features. It’s now become the most used transmission interface. Apple has now abandoned its patented Lightning interface on the iPhone for many years and switched to USB Type-C. As long as you own a computer, USB will always be a part of your life. If manufacturers don’t pay attention to the design of USB products, all kinds of issues will occur during use. As such a popular interface, it will drive users crazy if the connection fails during use. This is an issue that manufacturers and brands must solve for themselves.

The laptop with USB-C port
The laptop with USB-C port

USB Device Potential Issues and Examples

For USB products to function properly, three conditions need to be met for a successful connection, namely the host, cable, and device. When designing these three products, their signal transmission quality, power (power supply, voltage, and power consumption), stability, and connection accuracy must be considered. As long as there is an issue with any one of these, it will cause the product to fail to work at its intended level. In more severe cases, it could even damage the connected products, leading to repairs. This will not only cause manufacturers more money, but it could also damage their brand image.

The following is a situation Allion has handled with a past client, helping them identify issues and provide solutions:

  1. The host is a Windows PC or Apple/Android tablet.
  2. The device is an audio mixer, requiring 15W (5V/3A) for stable functionality.
  3. The host and device transmits USB 2.0 data and 15W of power through a USB Type-C cable
  4. When the host and device are connected via USB Type-C, power can be supplied for under ten seconds. However, the device will fail to be recognized and then re-identified once again.
  5. After that, there was a continuous loop of the device being re-identified repeatedly.
The host and device are connected via USB Type-C
The host and device are connected via USB Type-C

After analyzing deeper into the issue, we found that the problem was that after the D+/D- starts transmitting USB signals, crosstalk noise is also generated on CC. The PD chip misunderstands this noise as a PD packet, issuing a hard reset on a loop. Allion’s professional consulting team recommended this client make two improvements:

1. Do not twist the D+/D- and CC in the cable to prevent crosstalk noise from affecting the PD chip. This is because you don’t want them to be too close to each other. To verify this, perform the following two Cable SI tests to confirm performance improvement.

2.Increase D+/D- to suppress the crosstalk noise generated by CC in the device during signal transmission. To verify this, you can perform the following PD tests to find the issue and take care of it.

  • PD.PHY.ALL.4 Bus Idle Detection
  • PD.PHY.ALL.5 Receiver Interference Rejection

Faster, Easier, Better: The Most Trusted USB Product Testing Consulting Service

As a professional testing and consulting company, Allion is not only an official certification laboratory authorized by the USB-IF, but we also utilize our decades of experience to conduct customized testing for various clients, providing them with the best service we can.

With plenty of experience, Allion designs customized testing plans for USB-related products, providing the best consulting services for our clients and helping them eliminate issues they may encounter. This ultimately reduces the possibility of users returning their purchased products.

  • Customized Testing and Consulting Services
  • Compatibility Test
  • User Experience Test
  • Competitive Analysis and Quality Improvement Consulting
  • USB Certification Test


Allion can provide clients with fast and accurate evaluations that effectively shorten schedules for certifications. With collection of testing equipment, we have the most complete testing equipment in our laboratories, providing the best quality control for our clients.

  • Quickly build a USB-related testing laboratory
  • Quickly design development verification strategies
  • Quickly obtain certification planning


Allion has a complete range of hardware certification testing equipment and testing environments. With our testing solutions, we can ensure each client’s certification process is qualitative, quantitative, and reproducible. Through Allion’s professional support, we can assist our clients in obtaining accurate test results easily, ensuring the quality and performance of their products.

  • Provides more accurate results
  • Provides professional issue isolation and debugging support for our clients to make product development more convenient.


Not only does Allion have professional teams with decades of experience, but we also know how to design quantitative tests and user scenario simulations, allowing our clients to comply with requirements and user expectations. Allion’s professional teams can also provide suggestions for product modifications, assist with supplier management, and help with specifications requirements from international associations during product development. This further enhances the quality of our client’s products, ensuring high standards that comply with international specification requirements.

  • Provides a better and more complete experience for brands to establish ODM ecosystem plans
  • Provides more complete user scenario testing solutions

Allion Labs_Faster, Easier, Better

If you have any further needs for testing, verification, or consulting services, please feel free to explore the services online or contact us through the online form.