USB Port (Universal Serial Bus)

USB port

USB Port (Universal Serial bus)

Universal Serial Bus is a
Universal Serial Bus interface port of a device that is used to connect peripherals. USB Port is a plug and play device with inbuilt drivers in the Operating System. Most of the peripherals nowadays come with inbuilt USB ports. The older Parallel, serial port, and PS2 connectors interfaces were replaced by USB ports, as USB is having more transmission speed. The main advantage of the USB port is that it can connect 127 devices with greater speed and it also carries power
    USB Connection carries data as well as power so is also used to charge some device batteries such as smartphones, tablets, etc. USB Port comes with every Desktop computer, laptop, and tablet. Depending upon size and interface types of USB port connections are available

USB Port types

Depending upon interface and speed, USB ports are categorized in following different types


Connector TypeData Rate
USB-A USB-B12 mbps
This type of connection comes with all devices such as Personal computers, Smart TVs, etc. USB-A is rectangular in shape with an indication of how to insert it in port so there is no possibility of connecting the device wrongly. The size of type A also comes in USB 1.1, USB 2.0, and USB 3.0 but when USB 3.0 is connected to USB A the transfer speed is lower.
This type of connector is normally come with power devices and printer. The shape of B type connector is square with beveled top edges so they cannot be wrongly inserted.
USB-A Type and B type Pin connections
Pin NoConnectionColorDescription
1VccRed+ 5 Volt
2D-WhiteData – signal
3D+GreenData + Signal


When USB 2.0 was launched many peripheral devices such as CD writer, DVD writer, External Hard disk for storage, Pen Drive, also started manufacturing with USB adapters

USB Mini –A type and USB Mini-B type
Connector TypeData Rate
USB Mini-B USB Micro-A
USB Micro-B

480  Mbps
USB Mini-A Type and USB Mini-B type were invented for the small devices so the difficulty in fixing in USB A and B type connectors can be minimized. The devices using this type of connectors are mainly digital cameras, phones, etc.
Mini USB A Type and Mini B type Pin connections
Pin NoConnectionColorDescription
1VccRed+ 5 Volt
2D-WhiteData – signal
3D+GreenData + Signal
4IDNot connected
USB micro A type and USB Micro B type
When design using mini USB connectors become smaller, the need for Small and tiny compatible connector’s increased and micro USB connectors were designed. Micro USB connectors are widely used in modern cellphones and GPS devices which can charges devices as well as transfer data.
Micro USB-A Type and Micro B type Pin connections

USB micro A type and USB Micro B type

Pin NoConnectionColorDescription
1VccRed+ 5 Volt
2D-WhiteData – signal
3D+GreenData + Signal
4IDNot connected


USB Micro-B
Gen-1 —5 Gbps
Gen-2 — 10 Gbps
Gen-3.2 2 x 2— 20 Gbps
USB 3.0 is designed for faster communication and data transfer. USB 3.0 has changed a lot with the need for data transfer speed. It has changed from a speed of 5 Gbps to 20 Gbps with the invention of every new generation. Nowadays many devices come with USB 3.0 and 3.1 ports.

USB-C Type

·         USB-C type connector is a 24 pin connector little bit larger then Micro-B connector and USB –C connector has Reversible plug orientation and a data transfer speed up to 10 Gbps and power flow capacity of 100W. USB C has longer durability up to 10000 insertions.
USB-C — A pin layout
Pin. noConnectionDiscription
A1GNDGround return
A2SSTXp1Superspeed differential pair 1TX positive
A3SSTXn1Superspeed differential pair 1TX negative
A4V BUSBus power
A5CC1Configuration channel
A6Dp 1USB 2.0 differential pair, position 1, + ve
A7Dn 2USB 2.0 differential pair, position 1,  – ve
A8SBU1Sideband use –SBU-
A9V BUSBus power
A10SSRXn2SuperSpeed differential pair #4, RX, negative
A11SSRxp2SuperSpeed differential pair #4, RX, positive
A12GNDGround return

USB-C — B pin layout

Pin. noConnectionDiscription
B12GNDGround return
B11SSTXp1Superspeed differential pair 2 RX positive
B10SSTXn1Superspeed differential pair 2 RX negative
B9V BUSBus power
B8SBU2Sideband use –SBU-
B7Dn 2USB 2.0 differential pair, position 2, – ve
B6Dp 2USB 2.0 differential pair, position 2  + ve
B5CC2Configuration channel
B4V BUSBus power
B3SSRXn2SuperSpeed differential pair 3, TX, negative
B2SSRxp2SuperSpeed differential pair 3, TX, positive
B1GNDGround return

Due to the versatility of USB-C port, it has become an industry-standard nowadays and comes in every laptop, cell phone, and many other devices.

Thunder Bolt

Thunderbolt is an adapter that comes with computers and peripherals. This technology emerged in 2009 with the name ‘Thunderbolt’ and its next version was launched in about 2013 as ‘Thunderbolt2’ and It has a serial interface that mixes existing PCI express technology and Displays port technologies. Intel owns this technology but apple has developed it. Data transfer over long distances is possible due to thunderbolt. The first two generations of thunderbolt have a data transfer speed of 20 Gbps. latest version Thunderbolt 3 has a data transfer capacity of 40 Gpbs and the connectors resemble USB C.Thunderbolt cables are of two types they are used Copper and fiber depending upon the speed of data transmission and power transmission.

Above mentioned are the mainly used USB ports up to now, USB 4 is on the way to launch in every device. The data rate of USB 4 is 40 Gbps which is double the rate of USB 3.2 2 X 2 and will have backward compatibility up to USB 2,0 and above.

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