USB Over IP Hub: Extending USB Past the Cable Limit
USB was designed for a cable two metres long. Put a device server on the network and the device appears on a machine in another building, which is either a solution or a trap depending on what the device is.
Quick Answer
A USB over IP hub, also called a USB device server, presents USB devices to computers over Ethernet or Wi-Fi as though they were local. It suits low bandwidth, latency tolerant devices such as serial adapters, license dongles, programming cables and instruments. It is unsuitable for webcams, audio interfaces, storage used for active work and anything requiring isochronous transfers.
Which Devices Belong on a Device Server
| Device | Suitable | Reason |
|---|---|---|
| Serial adapter | Yes | Very low bandwidth, data tolerant of delay |
| Licence dongle | Yes | Tiny transfers, checked occasionally |
| Programming cable | Yes | Short bursts of configuration data |
| Test instrument | Often | Depends on polling rate and vendor software |
| Flash drive for file transfer | Workable | Slow compared with local, but functional |
| Webcam | No | Needs continuous isochronous bandwidth |
| Audio interface | No | Latency destroys usability |
| Video capture device | No | Bandwidth and timing requirements |
How It Works
Server side
The hub runs a small service that advertises attached devices on the network.
Client side
Driver software on the computer creates virtual copies of those devices, which then appear to applications as ordinary USB devices.
Protocols
Vendors use proprietary protocols, and some use the open USB over IP approach. Cross vendor compatibility is limited, so buy the paired products.
Reservation
Most systems allow a device to be claimed by one client at a time. Without proper release, a device can appear busy to everyone.
Practical Limits
- Latency of a few milliseconds is tolerable for serial work and fatal for audio.
- Network outages drop the device mid operation, which matters for long writes.
- Gigabit Ethernet is ample for everything in the suitable list.
- Power: many device servers supply standard port current, which is enough for adapters and dongles.
Real-World Applications
- Lab instruments accessed from several workstations without moving cables.
- Licence dongles shared by a team in one office.
- Remote configuration of equipment in a rack room.
- Thin clients using USB peripherals hosted centrally.
Related Guides
For wired networking on a laptop, read USB Ethernet hub. For the modern connector version, see USB-C Ethernet hub. For remote site networking, start with industrial USB 3.2 hub.
FAQ
Can I use a webcam through a USB over IP hub?
Almost never usefully. Webcams need continuous timing that the network cannot guarantee.
Is it the same as USB extension over Ethernet?
Similar goal, different mechanism. Extension products tunnel one link, while a device server shares devices between many clients.
Does it need software on both ends?
Yes. The hub runs the service and each client needs a driver or utility.
What network speed is needed?
Gigabit is more than adequate for the devices that suit this product category.