Quick Answer / Summary: A USB 2.0 A to B cable connects a host computer (Type-A plug) to peripheral devices with the square Type-B socket: printers, scanners, audio interfaces, Arduino boards and older external drives. It carries 480 Mbps and up to 500 mA. Order 28 AWG minimum for short runs, 24-26 AWG with a shielded jacket for anything over 2 m.
The A to B cable is the workhorse that made USB universal: flat Type-A into the computer, square Type-B into the printer. Twenty-five years later it still ships with office hardware because the socket is sturdy, keyed and cheap to manufacture. This guide lists every device class that still uses USB 2.0 A-to-B, explains the pinout so substitutions are safe, and gives a procurement checklist for bulk orders.
Devices That Use a USB 2.0 A to B Cable
The Type-B socket survives wherever the device is stationary and powered from the wall rather than the bus. Printers and multifunction copiers are the classic case, followed by flatbed scanners, studio audio interfaces, MIDI controllers, laboratory instruments, CNC controllers, and hobby boards including Arduino Uno and Mega, whose designers chose B for the robust mount.
USB-B vs USB 3.0 Type-B
USB 3.0 devices use a taller B connector with a separate section for the extra SuperSpeed pairs. A USB 2.0 A-to-B plug physically fits the lower section of a USB 3.0 B socket, but the link negotiates at 480 Mbps. Pure USB 2.0 devices reject nothing because their socket only accepts the standard B plug.
Pinout: Why Any Quality A-to-B Works
All four pins are straight-wired: pin 1 VBUS +5 V, pin 2 D-, pin 3 D+, pin 4 GND. There is no electronics inside a passive A-to-B cable, so compatibility depends entirely on build quality. Shielding (foil plus braid) and a ferrite bead at each end are what separate a cable that prints 200 jobs a day from one that drops the connection weekly.
Procurement Checklist for B2B Orders
Confirm connector orientation (straight or right-angle B for tight cabinets), conductor gauge against length, jacket material for the environment (PVC for office, braided nylon for workshops), and whether the buyer needs Hi-Speed certified construction for EMI-sensitive installs. For printer fleets, standardise on one length – usually 1.8 m or 3 m – to simplify spares.
A-to-B Cable Specification by Application
| Application | Recommended Length | Gauge | Shielding | Notes |
|---|---|---|---|---|
| Office printer | 1.8-3 m | 26-28 AWG | Foil + braid | Standard desk run |
| Audio interface | 1-2 m | 24-26 AWG | Foil + braid + ferrites | Short for latency-critical USB audio |
| Arduino / CNC | 1-2 m | 24 AWG | Foil + braid | Stable serial programming |
| Scanner station | 3 m | 26 AWG | Foil + braid | Keeps lamp EMI out of the data pair |
Real-World Application Scenarios
A 40-desk office standardises on 3 m shielded A-to-B cables for its shared printers; a maker space buys 1 m units for its Arduino benches to keep bench wiring tight; a recording studio uses short, double-ferrite cables from interface to laptop to avoid ground-loop noise.
Recommended Internal Resources
Editorial Note: Browse the USB Cables and Cords catalogue for A-to-B variants, Commercial USB Cables for fleet-standardised office cables, and USB Data Transfer Cables when two PCs must talk directly.
Frequently Asked Questions (FAQ)
Q: Are all USB A to B cables the same?
A: Electrically yes – four straight-wired pins – but gauge, shielding and connector plating vary widely. Cheap 28 AWG unshielded cable fails on long runs and in EMI-heavy environments.
Q: Can I use a USB 3.0 A to B cable on a USB 2.0 device?
A: Yes. USB 3.0 cables are backward compatible; the link simply runs at 480 Mbps. The reverse also works for USB 2.0-speed transfers into a USB 3.0 B socket, at reduced speed.
Q: Why does my printer drop offline with a 5 m A-to-B cable?
A: Five metres is the passive limit. Unshielded or thin-gauge 5 m cable frequently fails; drop to 3 m, or use a shielded 24 AWG cable if the run must stay long.
Q: What length A-to-B cable should I buy for a printer?
A: Measure the actual path and add 20 percent slack. Most office printers land at 1.8 m; floor-standing copiers usually need 3 m.