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Solve : only 7 usb? |
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Answer» Is there a computer/electronics reason that USB hubs stop at seven ports?Probably to maintain the data transfer rate. A USB 2.0 port only has a data transfer rate of 480Mbs divide that by 7 gives you ~68Mbs. Now that's fine for keyboards, mice, printers, etc but that would REDUCE the performace of USB hard drives, webcams & other bandwidth hungry peripherals. It's probably considered BAD practice to load anymore than 7 extra ports onto any one original port. A little bit like why you're not supposed to plug an electrical extension cord into another extension cord (except without the risk fire). You would have to have 40 USB ports plugged into a USB 2.0 to reduce it's performance to that of USB 1.0. Probably to maintain the data transfer rate. A USB 2.0 port only has a data transfer rate of 480Mbs divide that by 7 gives you ~68Mbs. err... that's true, but you'd need to have a hard drive or flash drive plugged into every port and copying data from them in order to do that. I don't think there is a limitation (standards wise) to the number of ports a hub may have.I wonder whether it has to do with power issues, since USB devices, to a varying degree depending on the device, are powered by the USB port. USB As A Power SourceQuote from: BC_Programmer on April 09, 2010, 11:30:42 AM err... I REALISED that after I did the numbers but I was hoping that I could still pull off a convincing pitch. Quote from: soybean on April 09, 2010, 11:42:09 AM I wonder whether it has to do with power issues, since USB devices, to a varying degree depending on the device, are powered by the USB port. USB As A Power Source They usually use another power source to bolster that of the usb ports (wall SOCKET).OK a friend of mine read this and said, if we use 2 hubs, then its officially called a hubahuba...and if we tape one hub on top of the others, they are thereafter called a hubabova. *blink ANYWAY...thanks for the answers. Quote from: mnkypprs on April 09, 2010, 12:45:07 PM if we use 2 hubs, then its officially called a hubahuba I like that! Some marketing person is GOING to pick up on that, expect to see it on shelves soon. I think Soy is right, it is a power issue. I have seen AC powered hubs that were designed to be stackable meaning the manufacturer expected a some what unlimited number of ports to be used. I'm sure there is a limit somewhere but it depends on the useage.USB devices can be daisy-chained up to 212 connections.....though i wouldn't recommend it. |
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