The USB Type-C connector succeeds the Micro-USB standard. Faster, leaner, and more reliable, the USB-C technology is designed to replace the confusing mess of USB cables in the market with a single type of cable. The standard connectors were designed to be more robust than many past connectors. This is because USB is hot-swappable, and the connectors would be used more frequently, and perhaps with less care, than previous connectors. The different A and B plugs prevent accidentally connecting two power sources. However, some of this directed topology is lost with the advent of multi-purpose USB connections (such as USB On-The-Go in smartphones, and USB-powered Wi-Fi routers), which require A-to-A, B-to-B, and sometimes Y/splitter cables. See the USB On-The-Go connectors section below for a more detailed summary description. USB PowerShare Feature". dell.com. 5 June 2013. Archived from the original on 8 November 2013 . Retrieved 4 December 2013. Ngo, Dong (August 22, 2014). "USB Type-C: One Cable to Connect Them All". c|net. Archived from the original on March 7, 2015 . Retrieved December 28, 2014.

USB2.0 provides for a maximum cable length of 5 meters (16ft 5in) for devices running at high speed (480Mbit/s). [88] Some non-standard USB devices use the 5V power supply without participating in a proper USB network, which negotiates power draw with the host interface. Examples include USB-powered keyboard lights, fans, mug coolers and heaters, battery chargers, miniature vacuum cleaners, and even miniature lava lamps. In most cases, these items contain no digital circuitry, and thus are not standard-compliant USB devices. This may cause problems with some computers, such as drawing too much current and damaging circuitry. Prior to the USB Battery Charging Specification, the USB specification required that devices connect in a low-power mode (100mA maximum) and communicate their current requirements to the host, which then permits the device to switch into high-power mode.Devices that draw no more than one unit are said to be low-power devices. All devices must act as low-power devices when starting out as unconfigured. For USB devices up to USB2.0 a unit load is 100mA (or 500mW), while USB3.0 defines a unit load as 150mA (750mW). Full-Featured USB-C Fabrics can support low-power devices with a unit load of 250mA (or 1250mW). USB takes full advantage of the additional processing power that can be economically put into peripheral devices so that they can manage themselves. As such, USB devices often do not have user-adjustable interface settings. The charging device identifies a charging port by non-data signaling on the D+ and D− terminals. A dedicated charging port places a resistance not exceeding 200Ω across the D+ and D− terminals. [50] :§ 1.4.7; table 5-3 MIDI Controllers: Musical instruments and MIDI controllers often use USB Type B connectors to establish a connection with computers for transmitting MIDI data, allowing musicians to control software synthesizers and digital audio workstations.

As of 2023, [update] USB consists of four generations of specifications: USB 1. x, USB 2.0, USB 3. x, and USB4. USB4 enhances the data transfer and power delivery functionality withSmith, Ryan (September 22, 2014). "DisplayPort Alternate Mode for USB Type-C Announced - Video, Power, & Data All Over Type-C". AnandTech. Archived from the original on December 18, 2014 . Retrieved December 28, 2014. In addition to limiting the total average power used by the device, the USB specification limits the inrush current (i.e., the current used to charge decoupling and filter capacitors) when the device is first connected. Otherwise, connecting a device could cause problems with the host's internal power. USB devices are also required to automatically enter ultra low-power suspend mode when the USB host is suspended. Nevertheless, many USB host interfaces do not cut off the power supply to USB devices when they are suspended. [100] a b Universal Serial Bus Cables and Connectors Class Document (PDF), Revision 2.0, USB Implementers Forum, August 2007, p.6, archived (PDF) from the original on April 27, 2015 , retrieved August 17, 2014 USB connectors have been increasingly replacing other types as charging cables of portable devices.