Editing USB (section)

== Connectors <span class="anchor" id="CONNECTORS"></span>==
{{Main|USB hardware#Connectors}}

The connectors the USB committee specifies support a number of USB's underlying goals, and reflect lessons learned from the many connectors the computer industry has used. The female connector mounted on the host or device is called the ''receptacle'', and the male connector attached to the cable is called the ''plug''.<ref name=USB30Spec/>{{rp|pages=2-5–2-6}} The official USB specification documents also periodically define the term ''male'' to represent the plug, and ''female'' to represent the receptacle.<ref>{{cite web |title=USB 2.0 Specification Engineering Change Notice (ECN) #1: Mini-B connector | website = USB Implementers Forum |url=http://www.usb.org/developers/docs/ecn1.pdf |date=20 October 2000 |url-status=live |archive-url=https://web.archive.org/web/20150412121600/http://www.usb.org/developers/docs/ecn1.pdf |archive-date=12 April 2015 |access-date=29 December 2014}}</ref>
[[File:USB Type-A plug B&W.svg|alt=USB Type-A plug|thumb|The USB Standard-A plug, once the most common type of [[USB connector]], now one of many legacy types of USB connector]]
The design is intended to make it difficult to insert a USB plug into its receptacle incorrectly. The USB specification requires that the cable plug and receptacle be marked so the user can recognize the proper orientation.<ref name=USB30Spec/> The USB-C plug however is reversible. USB cables and small USB devices are held in place by the gripping force from the receptacle, with no screws, clips, or thumb-turns as some connectors use.
[[File:USB-Micro-B-plug--and--USB-Mini-B-plug (cropped).jpg|thumb|USB Mini-B (right) and its successor USB Micro-B (left). These were the most common types of USB connector on smaller and portable hardware until the creation of [[USB-C|USB Type-C]].]]
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.

USB connector types multiplied as the specification progressed. The original USB specification detailed standard-A and standard-B plugs and receptacles. The connectors were different so that users could not connect one computer receptacle to another. The data pins in the standard plugs are recessed compared to the power pins, so that the device can power up before establishing a data connection. Some devices operate in different modes depending on whether the data connection is made. Charging docks supply power, and do not include a host device or data pins, allowing any capable USB device to charge or operate from a standard USB cable. Charging cables provide power connections but not data. In a charge-only cable, the data wires are shorted at the device end; otherwise, the device may reject the charger as unsuitable.

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