Sourcing USB hubs and docking stations

The upstream is the ceiling. Whatever the dock connects to the host with sets the total available for every data port behind it. A dock full of fast ports on a slow upstream is a dock whose ports are fast only one at a time.

So specify the behaviour, not the count. What each port delivers alone, and what each delivers with the others in use. Ask for the allocation in writing — a supplier who has designed the product can produce it, and one who assembled a reference board will send you a marketing sheet.

No bandwidth table appears here on purpose. The generation names have been revised and reused, so a table in a guide is wrong for somebody; specify the rate you require in gigabits per second and verify it on the host you actually sell alongside.

Ethernet, card readers and audio each behave differently under contention, and a card reader that is fine alone can crawl while a drive is copying. If your customers do a specific thing — photographers emptying cards, developers running two displays — test that thing rather than a synthetic benchmark.

And test with real hosts. Host compatibility is the largest single cause of returns in this category, and it is not predictable from a specification sheet. Buy a small spread of the machines your customers use and test on all of them.

Alternate mode. The connector's physical lanes are reassigned to carry a display signal directly. No driver, low latency, low processor load — but the host must support it. Many laptops do, many do not, and most phones do not. When the host does not, the video port is inert and the customer thinks the dock is broken.

Compressed video over ordinary USB. A driver on the host encodes the display and sends it as data. It works on hosts that do not support the alternate mode, which is its whole reason to exist, but it requires a driver installation, it consumes processor time and it behaves differently with fast-moving content.

So the specification must say which mechanism, and the listing must say it too. It is the difference between a product that works for a customer and one that cannot, and it is knowable before purchase — which makes it exactly the sort of thing that generates a bad review when it is hidden.

Two displays multiply the question. Whether two outputs can run independently, at what resolution and refresh rate, and whether that depends on the host or on a mode setting. Specify it per host family and test it.

Driver support is a maintenance commitment. If the dock relies on a driver, somebody has to keep it working across operating-system updates. Ask whose driver it is, how it is distributed, and what the update record has been — a dock whose driver stops working is a dead product with your brand on it.

Pass-through charging. Most docks accept power in and pass some to the host. Some is lost, and the loss depends on the design — specify the input required and the output guaranteed to the host with all ports loaded, rather than accepting a headline figure measured with nothing connected.

Heat. Docks run hot, particularly ones doing video conversion, and heat is what turns an intermittent fault into a returned product. Specify the enclosure material and thermal design and test under sustained full load in a warm room, not for two minutes on a desk.

The captive cable, if there is one. It is the most common physical failure: strain relief at the dock end, conductor gauge for the power it carries, and length. A captive cable also fixes the product's lifetime to that of its weakest part, which is a design decision worth making deliberately.

Enclosure and grounding. Metal enclosures help thermally and can help with interference, but they need proper grounding and can otherwise make emissions worse. This is a compliance interaction, not just a styling choice.

Certification. A dock is a digital device with high-speed signalling, so destination electromagnetic-compatibility requirements apply and are the most common failure at test. The USB logos are licensed and require certification through the standards body's programme, and marketplaces increasingly ask.

Business licence and business scope (经营范围) first, then the design question, which matters unusually much here: is this the factory's own board or a chipset vendor's reference design, who writes and signs the firmware, and who supplies and maintains any driver? A dock is a small computer and the answer decides whether a compatibility problem can be fixed.

Ask for the electromagnetic-compatibility test report by model and check the applicant. High-speed digital products fail this test more often than any other category in a 3C catalogue, and a report for a similar model is not evidence about yours.

Test on a spread of real hosts, with every port populated, for hours, in a warm room. Then repeat after an operating-system update, which is where driver-dependent docks fail.

Take one apart: the controller, the video bridge if there is one, the power path, the shielding and grounding arrangement, and the captive cable's termination.

Every supplier on this site is a manufacturer, and the registered-scope check is one of the things confirmed before a listing goes live.