Universal Serial Bus (USB)
What’s in it for you?
KNOW YOUR USB:A PRACTICAL GUIDE TO THE UNIVERSAL SERIAL BUS
The Universal Serial Bus has come a long way as a technology; it is now standard in today’s electronics and gadgets for work and play.
Computers and peripherals interact through USB ports. As you can see here, legacy serial and parallel ports once dominated the scene. Under this setup, a keyboard, mouse, external monitor, printer, and all other PC accessories have a corresponding custom port to communicate with the computer.
There were, however, problems with the usage of such legacy computer ports. For starters, peripherals might have been incompatible with the ports available. Data transfer also lagged with mere kilobytes per second although, between parallel and serial ports, parallel ports boasted faster transmission speed. Not all computer ports could run at once when in use under this scenario.
USB came along in the 1990s and changed computers and devices forever. There’s the standardization of ports replacing some, if not all, old computer sockets with a uniform one with supported cables and connectors. Data storage, transmission, and portability have also received a boost from USB.
Surely, you want to brush up on your knowledge about USB, the nitty-gritty of this handy, everyday technology from its history to terminology. And because electronics that use USB run aplenty, learning more about the versions, types, and solutions is indispensable. This technology is evolving to respond to ever-changing times, and you are on the right page.
WHAT DOES A USB DO?
From a then-struggling standard, USB has lived up to the universal in its name as millions, if not billions, of devices have adopted it.
What’s in it for you?
- Point of communication, plug and play. USB’s primary purpose is to connect devices to computers. This ease of use is evident in hot swapping such that you can insert a peripheral into a USB port or remove it, for that matter, without turning off the computer or tweaking some settings.
- Data transfer. The speed of transferring data between devices is the strongest suit of USB, whose theoretical transmission rate can reach up to 40 Gigabits per second. USB data-transfer rates are Low Speed, Full Speed, High Speed, SuperSpeed, and SuperSpeed+.
- Data storage. Wireless file-sharing technologies may have become the norm, but USB flash drives are still everywhere because they remain reliable and portable. These devices store with a memory capacity designed to accommodate movies, songs, and other large files.
- Battery charging. USB enables you to charge your phone and any portable device with batteries to your computer or wall outlet. The standardized USB connector ensures you can plug your device into a compatible port found on your laptop.
What’s more, USB-C can now charge laptops (your laptop’s USB-C port must support charging) and, if coupled with Power Delivery (PD), can offer faster charging times.
VERSIONS OF USB:
HISTORY OF RELEASES AND REVISIONS
A summary: Ajay Bhatt and his team invented USB, whose development began in 1994. The first version, USB 1.0, was released in 1996, but it was USB 1.1, which debuted in 1998, that gained extensive usage. The rest is history, as follows.
Prerelease
- USB 0.7 was a prerelease version of USB, although some considered it the first USB version with a release date of November 1994. Other than this information, not much is known about USB 0.7.
- USB 0.8 was another prerelease version, made known although not commercially available within the same year as USB 0.7 was.
- USB 0.9 was a prerelease version that debuted in April 1995. Like its predecessors, the release was not made available for commercial markets; however, it had a data-transfer rate of 12 Mbps.
- USB 0.99 was another prerelease version that was made known in 1995 but was not set for commercial availability.
- USB 1.0-RC was a release candidate, as indicated by the initials. It was released in November 1995.
USB 1.x
- USB 1.0 debuted in January 1996 and featured a Full Speed data transfer of 12 Megabits per second. Although it marked USB’s commercial debut, only a few products carried the technology.
- USB 1.1 was launched in August 1998 and led to broader commercial adoption and public acceptance. Its data transfer ranged from 1.5 Megabit per second at Low Speed to 12 Megabit per second at Full Speed.
This version is historic because it led to the creation of legacy-free PCs, whose legacy ports were replaced with USB ports or rendered obsolete. One stellar example is Apple’s iMac G3, which was released that same year; the computer lacked a floppy disk drive and featured USB 1.1 ports instead.
USB 2.0
- USB 2.0 debuted in April 2000 with much higher bandwidth. It has a maximum transfer rate of 480 Megabits per second, thus the name High Speed. USB 2.0’s faster data rate (USB’s connectivity and speed in general, actually) may have prompted the creation of USB flash drives. Moreover, the USB Implementers Forum (USB-IF) has made numerous changes to the USB 2.0, outlined here.
USB 3.x
- USB 3.0 was rolled out in November 2008, and it further sped things up with Superspeed or up to 5 Gigabits per second. USB 3.0 plugs and ports are color-coded blue (Pantone 300C) or bear the initials SS to distinguish them from USB 2.0 connectors. Consequently, USB-IF introduced changes to the USB 3.0 specification, as follows.
- USB 3.1 debuted in July 2013 with a SuperSpeedPlus (SSP) transfer rate of 10 Gigabits per second. According to its documentation, the specification is a performance enhancement to USB 3.0, paving the way for two variants:
- USB 3.1 Gen 1 has a transfer rate of 5 Gigabits per second and is synonymous with USB 3.0. With this, USB 3.1 Gen 1 effectively replaced USB 3.0.
- USB 3.1 Gen 2 has a transfer rate (described as SuperSpeedPlus) of 10 Gigabits per second. As with the above, USB 3.1 came to be known as USB 3.1 Gen 2.
With USB 3.2 superseding the older 3.x specifications, things are bound to get confusing with the names. Accordingly, the USB group has come up with the following guideline:
USB 3.2 Gen 1 × 1
(a.k.a. USB 3.0 and USB 3.1 Gen 1)Universal Serial Bus (USB)
Developed by Compaq, Hewlett-Packard, Intel, Lucent, Microsoft, NEC and Philips.
Contents
- 1 Pinout (Normal)
- 2 Pinout (Mini)
- 3 Pinout (USB 3.0)
- 4 Technical specs
- 4.1 Features
- 4.2 Bandwidth
- 4.3 Definitions
- 4.4 Power usage:
- 4.5 Voltage
- 4.6 Shielding
- 4.7 Cable
- 4.7.1 Shielded
- 4.7.2 Non-shielded
Pinout (Normal)
Series “A” plugs are used towards the host system and series “B” plugs are used towards the USB device.
Pin Name Description 1 VBUS +5 VDC 2 D- Data – 3 D+ Data + 4 GND Ground Pinout (Mini)
5 4 3 2 1 ___________ |_˙ ˙ ˙ ˙ ˙_| \ / (at the cable) \_____/
5 4 3 2 1 ___________ | . . . . . | \ / (at the cable) |_________|
Pinout (USB 3.0)
Connectors are backwards compatible with USB 1.1/2.0. The original 4 pins are still there. Expected transfer rate 4.7Gb/s.
Pin Name Description 1 VBUS +5 VDC 2 D- Data – 3 D+ Data + 4 GND Ground 5 USB3_RX USB 3.0 Data Receive (differential) 6 USB3_RX USB 3.0 Data Receive (differential) 7 GND Ground 8 USB3_TX USB 3.0 Data Transmit (differential) 9 USB3_TX USB 3.0 Data Transmit (differential) Technical specs
Features
- True Plug’n’Play.
- Hot plug and unplug
- Low cost
- Easy of use
- 127 physical devices
- Low cost cables and connectors
Bandwidth
- High speed: 480 Mbps speed (in USB 2.0 and above)
- Full speed: 12 Mbps speed (requires shielded cable)
- Low speed: 1.5 Mbps speed (non-shielded cable)
Definitions
USB Host = The computer, only one host per USB system.
USB Device = A hub or a Function.Power usage:
Bus-powered hubs: Draw Max 100 mA at power up and 500 mA normally.
Self-powered hubs: Draw Max 100 mA, must supply 500 mA to each port.
Low power, bus-powered functions: Draw Max 100 mA.
High power, bus-powered functions: Self-powered hubs: Draw Max 100 mA, must supply 500 mA to each port.
Self-powered functions: Draw Max 100 mA.
Suspended device: Max 0.5 mAVoltage
- Supplied voltage by a host or a powered hub ports is between 4.75 V and 5.25 V.
- Maximum voltage drop for bus-powered hubs is 0.35 V from it’s host or hub to the hubs output port.
- All hubs and functions must be able to send configuration data at 4.4 V, but only low-power functions need to be working at this voltage.
- Normal operational voltage for functions is minimum 4.75 V.
Shielding
Shield should only be connected to Ground at the host. No device should connect Shield to Ground.
Cable
Shielded
- Data: 28 AWG twisted
- Power: 28 AWG – 20 AWG non-twisted
Non-shielded
Cable colors
Pin Name Cable color Description 1 VBUS Red +5 VDC 2 D- White Data – 3 D+ Green Data + 4 GND Black Ground
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