USB 3.0 Type-A to Type-A Cable Wiring Options

Many users may assume there is only one type of wiring for USB 3.0 Type-A Male to Type-A Male Cable. In fact, there are three different wiring configurations for different applications.

Typical USB Type-A Male to Type-A Male cable. (Image source: Newnex)

Standard USB 3.0 A to A Wiring

USB 3.0 specification lists only one wire connection for USB 3.0 Standard-A Male to USB 3.0 Standard-A Male cable assembly. This cable intended to use for host-to-host connection, such as for operating system debugging.

For such applications, the wiring (Table 1) will be:

• The 5 V VBUS pin should not be connected to prevent current backflow to either USB host port.
• The Pin-to-Pin connection for the SuperSpeed signal data pairs is not straight through but crossed over, so that the TX pair is connected to the RX pair, while the RX pair is connected to the TX pair.

Table 1: Standard USB 3.0 A to A Wiring. (Source Newnex)

Custom USB 3.0 A to A Special Wiring #1 – With VBUS and Data Pair Crossed-Over

Despite the wiring configuration for host-to-host connection application (as listed is Table 1 above), users sometimes need USB 3.0 A to A cable to connect with some types of adapters for host-to-device connection applications.

For such applications, the wiring (Table 2) will be:

• The 5 V VBUS needs to be connected to provide USB bus power.
• The Pin-to-Pin connection is crossed over for the SuperSpeed Data Pair.

Table 2: Custom USB 3.0 A to A Special Wiring #1. (Source: Newnex)

Custom USB 3.0 A to A Special Wiring #2 – With VBUS and Data Pair Straight Through

For some other special applications, in which all wire connections for USB 3.0 A to A cable need to be connected straight through with certain types of straight-through adapters (e.g, USB 3.0 female to female coupler for wall plate) for host-to-device connections.

For such applications, the wiring (Table 3) will be:

• The 5 V VBUS need to be connected to provide USB bus power.
• The Pin-to-Pin connection is straight through for the SuperSpeed Data Pair.

Table 3: Custom USB 3.0 A to A Special Wiring #2. (Source: Newnex)

Summary

Not all USB 3.0 Type-A to Type-A cables have the same wiring configuration. Depending on the application, some have the power pins connected, some do not. Some have the data line pins cross-connected, some do not. So be sure to check the wiring configuration you need for your USB 3.0 A to A cable before you order to ensure you’re getting the right one.