1. USB Overview and Evolution:
– USB is an industry standard for data exchange and power delivery among various electronics.
– USB replaced interfaces like serial ports, parallel ports, game ports, and ADB ports.
– USB is used in keyboards, mice, cameras, printers, smartphones, and more.
– USB-C connector is the latest standard, supporting power up to 240W and various functionalities.
– USB4 combines multiple protocols on a single interface, supporting speeds up to 80Gbit/s.
– USB consists of four generations: USB 1.0, USB 2.0, USB 3.0, and USB4.
– USB4 enhances data transfer and power delivery with a tunneling architecture.
– USB4 supports Thunderbolt 3 protocols, PCIe, and DisplayPort.
– Each USB specification sub-version supports different signaling rates.
– USB provides power delivery for devices, extending limits up to 240 watts.
2. USB Connector Types and Standards:
– USB connectors include receptacles and plugs.
– Different USB standards have specific connector types.
– USB 3.0 introduced SuperSpeed USB with new signal coding schemes.
– USB 3.2 offers different operation modes like Gen1×1, Gen1×2, Gen2×2.
– USB4 v2.0 has a max speed of 10Gbit/s with one-lane operation modes.
– USB connectors have evolved from legacy Type-A and Type-B to modern Type-C.
– Type-A and Type-B connectors came in Standard, Mini, and Micro sizes.
– Type-C connector is reversible and supports various functionalities.
– USB specifications offer backward compatibility, though with reduced capabilities.
3. USB Objectives and Benefits:
– USB simplifies the interface between personal computers and peripheral devices.
– USB is self-configuring, eliminating the need for user adjustments.
– USB connectors are standardized, allowing peripherals to use most receptacles.
– USB devices can manage themselves, utilizing additional processing power.
– USB is hot-swappable, enabling device exchange without shutting down the host computer.
4. USB Speed Evolution and Technology Overview:
– USB 3.0 introduced USB Attached SCSI Protocol (UASP) for faster transfer speeds.
– USB 3.1 (SuperSpeed+) doubled signaling rate to 10Gbit/s.
– USB 3.2 introduced two additional SuperSpeedPlus operation modes.
– USB4 supports Thunderbolt 3 protocol and 40Gbit/s throughput.
– USB4 2.0 specification released in September 2022 with 120Gbit/s speeds.
– USB4 supports Thunderbolt 3, USB3.2, and USB2.0 backward compatibility.
– USB4 architecture allows sharing a high-speed link with multiple device types.
– USB4 supports various technologies like DisplayPort, PCI Express, and Thunderbolt 3.
5. USB Power Delivery Standards and System Design:
– USB Battery Charging Rev. 1.0 allowed 7.5W power.
– USB Power Delivery Rev. 1.0 enabled 100W power with FSK protocol.
– USB Type-C Rev. 1.0 introduced 15W power specifications.
– USB Power Delivery Rev. 2.0 enhanced power delivery to 100W.
– USB Power Delivery Rev. 3.1 reached 240W power capacity.
– USB system consists of a host with one or more DFP.
– Multiple peripherals form a tiered-star topology.
– Up to five tiers are allowed with USB hubs.
– A USB host may have multiple controllers with up to 127 connected devices.
– USB devices are linked in series through hubs, with endpoints on the connected device.
Universal Serial Bus (USB) is an industry standard that allows data exchange and delivery of power between many various types of electronics. It specifies its architecture, in particular its physical interface, and communication protocols for data transfer and power delivery to and from hosts, such as personal computers, to and from peripheral devices, e.g. displays, keyboards, and mass storage devices, and to and from intermediate hubs, which multiply the number of a host's ports.
 | |||
 The current connector for USB, Thunderbolt, and other protocols, USB-C (plug and receptacle shown) | |||
| Type | Bus | ||
|---|---|---|---|
| Production history | |||
| Designer | |||
| Designed | January 1996 | ||
| Produced | Since May 1996 | ||
| Superseded | Serial port, parallel port, game port, Apple Desktop Bus, PS/2 port, and FireWire (IEEE 1394) | ||
USB was originally designed to standardize the connection of peripherals to computers, replacing various interfaces such as serial ports, parallel ports, game ports, and ADB ports. Prior versions of USB became commonplace on a wide range of devices, such as keyboards, mice, cameras, printers, scanners, flash drives, smartphones, game consoles, and power banks. It has evolved into a standard to replace virtually all common ports on computers, mobile devices, peripherals, power supplies, and manifold other small electronics.
In the current standard the USB-C connector replaces the many various connectors for power (up to 240 W), displays (e.g. DisplayPort, HDMI), and many other uses, as well as all previous USB connectors.
As of 2024,[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 with
a connection-oriented, tunneling architecture designed to combine multiple protocols onto a single physical interface, so that the total speed and performance of the USB4 Fabric can be dynamically shared.
USB4 particularly supports the tunneling of the Thunderbolt 3 protocols, namely PCI Express (PCIe, load/store interface) and DisplayPort (display interface). USB4 also adds host-to-host interfaces.
Each specification sub-version supports different signaling rates from 1.5 and 12 Mbit/s total in USB 1.0 to 80 Gbit/s (in each direction) in USB4. USB also provides power to peripheral devices; the latest versions of the standard extend the power delivery limits for battery charging and devices requiring up to 240 watts (USB Power Delivery (USB-PD)). Over the years USB(-PD) has been adopted as the standard power supply and charging format for many mobile devices, such as mobile phones, reducing the need for proprietary chargers.
