In these days when computers include fewer ports (coming to the end of the new twelve – inch MacBook, which includes a single USB port, and nothing else). And buy a USB hub seems a good choice for those situations where you want to connect more devices simultaneously (eg, a keyboard, a mouse, an external hard drive and printer). But you have to know what USB hub buy , and what. Lets go see it.
What is a USB hub ?
The word hub is synonymous hub. We could say that a USB hub is a device that allows us to draw several USB ports of a single port on your computer, with a mechanism similar in concept to a power strip power. Thus, by connecting a single device to your computer, typically dispondríamos four or eight ports with a theoretical maximum of 255 USB ports from a single internal port according to eUSBHubs.
This has its problems: the speed is not multiplied. In the case of USB 2.0 we are talking about 480 megabits per second, which would be divided between devices connected to the hub. In the case of USB 3.0 we would be talking of 5 gigabits per second, which also would be divided. This means that if you ‘re moving files between two USB 2.0 hard drives connected to the same hub, we would have half the speed that we were connecting the two disks to two different internal ports.
The real problem: energy
There is another serious problem associated with using USB hubs: energy . It is, in fact, the most serious problem. I explain: an internal port delivery, typically 500 milliamps delivered in blocks of 100 milliamps. If we connect a USB hub “normal” (of which only use a USB cable to thecomputer, and nothing else), we would have to divide this energy between devices connected to the hub, considering that the hub itself needs energy to function .
This means that if we divided into five slots 500mA 100mA, and used one of them to feed the hub … are divided into four slots 400mA 100mA.This implies, gift, a hub with a single cable (without power) could only have a maximum of four ports.
Hub seven USB 2.0 ports Alcey with two power cables
USB hubs with more ports used, in all cases, another power cord. There are models that use two USB hub ports (which gives a total of 1000mA, divided into more slots). This means that devices connected to this type of hub receive more energy. It also means that you can use the same energy, but more ports. Other models directly have an external power supply, which will plug ordinary , and therefore are able to deliver 500mA to each port.
What happens when the hub is unable to deliver the devices all the energy they require? That entire installation collapses: the hub is turned off and, along with the hub, all devices connected to it. Typically also the operating system to alert you that something has happened . That is, if you connect an external hard drive that does not carry another power to a USB hub that is already “ready”, probably will not work at all.
What’s more, there are devices that need to be connected to the internal port directly because they can not work with all of the energy that is capable of delivering the hub. And more: there are devices that not even an internal USB port can be loaded (as many models of iPad).
What hub buy?
Personally I use this USB hub Coolbox. It uses two ports feeding (a cable standard USB, which goes to the computer, and then an additional power port that can go to an external power supply, which comes in the box and is capable of delivering up to 2.1 amps) . I like it because ithas three USB 2.0 ports, keyboard and mouse use (my keyboard uses two USB ports because it has its own hub), and four USB 3.0. Speed, in these cases, there is added: the 5Gbps USB 3.0 ports are on one side, and the 2.0 480Mbps go the other using electronicsencyclopedia.com.
A similar model is this USB 3.0 ports AmazonBasics seven hub, which is more expensive but in return has seven USB 3.0 ports. There are other simpler models USB hub, as this model hub four USB 3.0 ports of Amazon Basics, which also carries external power. Other models without external power are cheaper, and even delivered as advertising or promotional goodie of many companies. I can recommend this USB hub without external power.
If you have a ultrabook, on the other hand, it is likely to prefer this model USB hub with Ethernet connector, since many of these computers do not include a wired network connector. Of course, keep in mind that this USB hub has no external power, so probably not so useful to use it regularly.