The USB-IF uses a tree of known, good, USB devices to verify interoperability and functionality of a USB device. This tree is referred to as the Gold-tree.

The gold-tree is supposed to consist of USB-IF certified consumer devices that are widely available in the market. Unfortunately, the shelf-life of consumer products is limited and some items become difficult to find as time goes by.   As a result, the USB-IF will no longer identify specific makes and models of products for the gold-tree.  The shelf life and availability of consumer products is just too short and is difficult to maintain.  Because there is nothing special about the peripherals and hubs, except being USB Certified, product classes and types are specified.

The test procedures for using the candidate gold-tree may be used.  Please download the GoldSuite Test Procedure.

Devices that are both self-powered and bus-powered must be tested using bus-power.

Self-powered devices must be checked for bus powered operation.  Self-powered devices that enumerate on bus power must be tested as bus-powered.

All USB peripherals and hubs are required to enumerate on a SuperSpeed host controller and pass all applicable tests within USB30CV.

All USB peripherals, hubs, and hosts are required to enumerate on a SuperSpeed host controller and pass all applicable tests using the USB 3.1 interoperability test procedures.

Hubs and compound devices:

When testing hubs or compound devices, attach them to the highest operational tier level. Typically, that will be tier level 4. If the compound device contains another embedded hub, then attach to tier level 3.  Move gold tree devices on the branch to the exposed downstream ports on the hub or compound device.  If the hub under test is bus-powered, only low-powered peripherals, such as the mouse, should be attached to the bus-powered hub.

Hubs with no embedded devices:
·   Run USB20CV chap 9 and 11 on the hub
·   Run interoperability on the EHCI with 3.1 gold device(s) attached

Hubs with embedded devices (compound):
·   Run USB20CV on the hub and on each embedded device
·   Concurrently run interoperability on the EHCI on all embedded devices

Isochronous Devices:
·   High-speed isochronous DUTs are simply added to the USB 3.1 tree and must operate concurrently with the hi-speed camera.

Vendors are encouraged to test their devices against a variety of hosts and peripherals and not to rely solely on the USB-IF Gold-tree for validation.

Please see the USB 2.0 Compliance Test Program for the tests that are required for USB 2.0 Certification.

Effective immediately testing against the backwards compatibility interoperability tree is no longer required for compliance. The standard interoperability tree catches all failures found on the backwards compatibility tree.

Much like how a monitor with a built in USB hub must demonstrate the ability to simultaneously operate the USB hub and display video, so must a USB Type-C device capable of wireless charging demonstrate wireless charging capability while interoperating in various states .This compliance update clarifies that USB developers, seeking certification of their wireless charging capable USB products, are required to provide devices that demonstrate the wireless charging capabilities of their product.

Figure 9-1 in Section 9.1.1 of the USB 2.0 Specification identifies device states where suspend must be supported.  Peripherals are required to support the suspend state whenever VBus is powered, even if bus reset has not occurred.  The "Dead Battery" supend current test measures current consumed while the peripheral is in the "powered" state. 

The "Dead Battery" suspend current test procedure is a required compliance test for all upstream USB ports.  This procedure measures the ability of the peripheral to drop from unconfigured current to suspend current prior to bus reset.  The test procedure is identified at http://compliance.usb.org/index.asp?UpdateFile=Battery Charging#1.

It is common for a downstream port to provide power while suspended.  A powered suspend state is necessary for remote wakeup to function.  Also, a powered suspend state is becoming increasingly popular on PCs and hubs to enable USB battery charging, even if the PC is not operating.  Power is a limited resource and peripherals that do not have batteries (or have batteries but do not use USB to charge their batteries) must limit power consumption to suspend current levels.  Limiting current consumed to suspend levels allows any extra power to be diverted to adjacent downstream ports to be used for battery charging.  An exception is made for products with dead or weak batteries. Products with dead or weak batteries are allowed to draw up to 5 unit loads during the powered state suspend test. Refer to the connect timing ECN for more details on this exception.