A USB cord connects devices to transfer data, charge batteries, or supply power. These flexible cables use the Universal Serial Bus standard to link computers, phones, peripherals, and other electronics.
USB cords carry both data and electrical power through four wires inside a protective jacket. Two wires transmit data, while the other two provide power. Most modern cords use standardized connectors that fit multiple device types.
The host device (usually a computer) supplies power to connected peripherals. Data transfer happens through differential signaling, where changes in voltage represent binary data. This allows USB cords to handle both tasks simultaneously.
| Type | Max Speed | Power Delivery | Common Uses |
|---|---|---|---|
| USB-A | 480 Mbps | Up to 2.5W | Keyboards, mice, flash drives |
| USB-B | 480 Mbps | Up to 2.5W | Printers, external hard drives |
| Micro-USB | 480 Mbps | Up to 15W | Older smartphones, power banks |
| USB-C | 40 Gbps | Up to 240W | Laptops, modern smartphones, tablets |
| Lightning | 480 Mbps | Up to 18W | Apple devices |
Most people use USB cords primarily for charging mobile devices. A standard micro-USB cord can deliver up to 15 watts of power, enough to charge smartphones and tablets. Many laptops now use USB-C ports both for charging and data transfer, with some models supporting up to 100 watts of power delivery.
Data transfer remains another key function. While older USB 2.0 standard offers 480 Mbps speeds, modern USB 3.2 and USB4 standards can transfer data at rates up to 40 Gbps. This makes USB cords essential for connecting external storage devices, cameras, and other peripherals to computers.
I've used USB cords to connect my smartphone to my computer for both charging and transferring photos. The same cord works for charging my wireless earbuds' case and connecting a USB microphone to my laptop for recording.
Many people assume USB cords can only connect to computers, but they work with many devices including game consoles, car stereos, and even some home appliances. Another common misconception is that all USB cords are interchangeable - while most standard-A to micro-B cords work similarly, high-speed data transfer requires specific cable designs.
According to the USB Implementers Forum, there are over 16 billion USB ports in use worldwide. The organization notes that USB technology continues evolving, with new versions offering faster data transfer and higher power delivery capabilities.
When selecting a USB cord, consider:
For most everyday uses, a good quality USB-C to USB-C cord will work with modern smartphones, tablets, and laptops. Always check your device manufacturer's recommendations for compatible cables.