USB A to USB B Cable: What It Is and What It Connects
A USB A to USB B cable is one of the most dependable interconnects in business equipment: the rectangular USB-A end plugs into a computer, hub, or docking station, and the squarish USB-B end plugs into the device – a printer, scanner, external audio interface, or industrial unit. It is the default direct connection for office printers and a large share of lab and production equipment. This guide covers what the cable is, the devices that use a USB-B port, the difference between the USB 2.0 and USB 3.0 versions, and how to choose the right one for a specific machine.
Quick Answer / Technical Summary
A USB A to USB B cable connects a USB-A host port (a computer, hub, or docking station) to a USB-B device port (printers, scanners, external audio interfaces, legacy external drives, and much lab and industrial equipment). The USB 2.0 version carries 480 Mbps over four wires, and the USB 3.0 version carries 5 Gbps over a larger nine-pin B connector. It is the standard direct-connection cable for printers and many industrial devices, and the right choice comes down to the device’s port shape, the required speed, and the run length.
What a USB A to USB B Cable Looks Like
The A end is the familiar rectangular USB-A plug that fits host ports. The B end is a squarish plug – on USB 2.0 it is a tilted square, and on USB 3.0 it is a larger rectangle with an added L-shaped tongue inside.
That B-end shape is the fastest way to confirm you are holding the right cable before you connect a machine.
What Devices Use a USB-B Port
Printers are the dominant user – most office and production printers take a USB-B port for the direct computer connection. Scanners, external audio interfaces, legacy external hard drives, and a large share of medical, lab, and industrial controllers also use USB-B.
If the device side has a squarish port, an A-to-B cable is almost certainly the match.
USB 2.0 vs USB 3.0 A-to-B
The 2.0 version runs 480 Mbps and uses a four-pin B connector; the 3.0 version runs 5 Gbps and uses a nine-pin B connector. A USB 3.0 B plug will not physically fit a USB 2.0 B socket, but a 2.0 B cable does work in a 3.0 B port at 2.0 speed – backward compatible.
Most printers still use USB 2.0 B, so for a printer the 2.0 cable is the normal, correct choice.
How to Choose the Right A-to-B Cable
Match the version to the device’s port, keep passive cable length within the practical 1.5-5 m range, and for industrial environments choose a cable with braided shielding and firm strain relief.
For a printer fleet, standardizing on a shielded 2.0 A-to-B at 2-3 m covers nearly every machine and keeps spares simple.
Technical Specifications & Performance Benchmarks
| Feature | USB 2.0 A-to-B | USB 3.0 A-to-B | Note |
|---|---|---|---|
| Speed | 480 Mbps | 5 Gbps | Printers need 2.0-class speed only |
| B-end pins | 4 (+ 2 shield tabs) | 9 | Count the pins to identify |
| B-end shape | Tilted square | Rectangle + L-tongue | 3.0 will not fit a 2.0 port |
| Backward fit | Works in a 3.0 B port | Will not fit a 2.0 B port | 2.0 is the safe universal pick |
| Typical use | Printers, scanners, audio | Fast external devices | Match the device, not the max |
Industrial & Enterprise Application Scenarios
- Office Printer Fleet: A standard shielded USB 2.0 A-to-B at 2 m covers the deskjet and production printers on the floor, with simple spares.
- Scanning Station: A flatbed scanner takes the A-to-B cable directly to a workstation for batch digitization without a network hop.
- Audio Interface: A studio audio interface with a USB-B port connects straight to the recording computer for a low-latency, driver-simple link.
- Industrial / Lab Unit: A controller or instrument with a USB-B port uses a shielded A-to-B cable for a stable direct data connection on the bench.
System Integration & Recommended Connectivity Infrastructure
To build a complete, single-cable workstation or equipment-cabinet connectivity stack, pair these USB cable and connector products with our certified data and power interconnect range:
- usb extension cable: When the A-to-B run is short of the device, a usb extension cable on the A side adds reach without touching the device’s B port.
- adapter series: The adapter series covers the conversion cases an A-to-B cable does not – for example, when the host side is USB-C instead of USB-A.
- type c-hub: On a USB-C-only host, a type c-hub provides the USB-A port that the A-to-B cable needs on the computer side.
- usbA/C to lan cable: For equipment where a direct cable is impractical, a usbA/C to lan cable or a network path can replace the point-to-point A-to-B run.
Frequently Asked Questions (FAQ)
Q: What is a USB A to USB B cable used for?
It connects a USB-A host port (computer, hub, docking station) to a USB-B device port – most commonly printers, but also scanners, external audio interfaces, legacy external drives, and lab or industrial equipment.
Q: What is the difference between USB 2.0 and USB 3.0 A-to-B cables?
The 2.0 version runs 480 Mbps with a four-pin tilted-square B connector; the 3.0 version runs 5 Gbps with a larger nine-pin B connector. A 3.0 B plug will not fit a 2.0 B port, but a 2.0 cable works in a 3.0 port at 2.0 speed.
Q: Which A-to-B cable should I buy for a printer?
A USB 2.0 A-to-B cable – most printers use a USB 2.0 B port, and 480 Mbps is far more than a print job needs. Choose a shielded, 2-3 m cable for a typical office run.
Q: Does a USB A to USB B cable work both ways?
The connection itself is the same physical cable regardless of which end you name first – ‘A to B’ and ‘B to A’ are the identical product. Data flows between host and device over the link.