Through USB cables, various external devices, like keyboards, mice, flash drives, printers, and other digital media devices can be connected to a computer. Since its inception, USB has become extremely popular and a standard connection technique used by most people. Other than that, it is also used as a power cord between an adapter and a device.
USB has a standard design which is followed across all major electronics and computer industries. The cables consist of only plugs, while devices have receptacles to insert the plugs. The cables have a maximum length of 5 meters as data transferring is not possible with longer cables.
Host systems have Type A receptacles, and if at all devices have receptacles, then are of Type B. Normally, a USB cable has a Type A plug on one end, and a Type B plug on the other. However, there are different types of USB cables with differing plugs and receptacles, as mentioned here.
The first USB cable had only Type A and Type B plugs, as well as receptacles. After the invention of USB 2.0, it came with additional mini Type B plugs and receptacles. Type A connectors are flat and rectangular in shape and plug into downstream ports on the host system. These types are found on devices with a USB connector permanently fixed on them.
Type B connectors are square, beveled at the corners, are plugged into upstream sockets and are used when devices need to be plugged in at one end of the cable. Smaller devices like PDAs or digital cameras come with mini Type A or mini Type B connectors. Recently, a micro-USB connector was launched and used in latest mobile phones and PDAs.
Type A to Type A
This cable is used to connect two host devices or hubs with each other. Both USB devices need to have the Type A connector. The cable is a passive one, and can be useful for connecting scanners, printers, or hubs with the host system, generally a computer. However, this cable is not useful for connecting two computers via USB.
Type A to Type B
This is the most common of all cables, and connects any standard peripheral device to a host system. The flattened connector is the Type A connector which is plugged into downstream sockets on the host system. The Type B connector is square in shape and its corners are beveled. It is plugged into upstream sockets on devices.
The mini-b connector is small, a little bit square and is plugged into upstream sockets present on certain devices like digital cameras and cell phones. It should be noted that not all small devices can be connected using this cable, and is therefore essential to go through user manuals of digital and video cameras to know their compatibility.
Type A to Mini B (4 pin)
This latest addition to USB is exclusively used to connect specific devices to a host system. It has a flat-headed, rectangular shaped Type A connector at one end and a mini Type B connector which is small and a little square in shape at the other end. Video and digital cameras of leading brands use this cable. Check the manual before purchasing this cable.
Type B to Type B
This cable has Type B connectors on both ends. One end has a bracket assembly which can be screwed on to a wall plate, while the end has the usual Type B connector. This type of cable is used mostly by AV installers, since it helps in connecting a laptop to a separate wall plate instead of connecting it directly to a white-board.
Of late, wireless USB has become popular among users as it provides more power efficiency. However, USB cables are still very much in use as people trust a wire to provide assured connectivity. Knowing the various types of USB cables will surely help while purchasing a new one.