The modes have differing hardware and cabling requirements. There are five speeds for USB data transfer: Low Speed, Full Speed, High Speed (from version 2.0 of the specification), SuperSpeed (from version 3.0), and SuperSpeed+ (from version 3.1). The three sizes of USB connectors are the default or standard format intended for desktop or portable equipment, the mini intended for mobile equipment, which was deprecated when it was replaced by the thinner micro size, all of which were deprecated in USB 3.2 in favor of Type-C. The mini and micro formats may connect to an AB receptacle, which accepts either an A or a B plug, that plug determining the behavior of the receptacle. A USB cable, by definition, has a plug on each end-one A (or C) and one B (or C)-and the corresponding receptacle is usually on a computer or electronic device. Each format has a plug and receptacle defined for each of the A and B ends.

Thus, USB cables have different ends: A and B, with different physical connectors for each. Only downstream facing ports provide power this topology was chosen to easily prevent electrical overloads and damaged equipment. Unlike other data buses (such as Ethernet), USB connections are directed a host device has 'downstream' facing ports that connect to the 'upstream' facing ports of devices.

USB has been selected as the standard charging format for many mobile phones, reducing the proliferation of proprietary chargers.Ĭomparison of USB connector plugs, excluding USB-C type plugs The USB standard included power supply to peripheral devices modern versions of the standard extend the power delivery limits for battery charging and devices requiring up to 100 watts. All versions of USB specify cable properties version 3.x cables include additional data paths. Higher-speed development of the USB standard gave rise to another family of connectors to permit additional data paths. The initial versions of the USB standard specified connectors that were easy to use and that would have acceptable life spans revisions of the standard added smaller connectors useful for compact portable devices.

Type-A receptacle (inverted, so the contacts are visible).8-pin Mini-B plug, a proprietary connector used on many older Japanese cameras for both USB and analog AV output (This strongly resembles the 8-pin Micro-B plug which often has only 5 pin positions occupied.).

Cen tech battery charger schematic