Hi, i bought an alfa wifi adapter with realtek rtl8187 moderboard, when i plug it to computer using 10 meters usb cable it show me the message: usb device not recognized. but it appear on Device manager and wifi management softwares (but no wifis shown) .
but when i plug it to other cables (5meters and lower) it work without problems .
what is the problem please ? this cable was workin great with my old alfa with the ralink moderboard !
thank's in advance

2 Years
Discussion Span
Last Post by mouaadable

That's beyond the distance we expect USB to function. Yes it might work with say an older device if said device was different in any way (USB 1 vs 2?)

To fix this I'd try those "10 Meter (32 Foot) USB 2.0 Active Extension Cable" versus a simple cable.


no both of the devices are 2.0 (my old adapter and this adapter)
all posibilites are :
my rtl8187 + 10 meters usb cable = usb device not recognized
rtl8187 + 5 meters + 1 meter usb cables = working very well

rtl8187 + 1 meter usb cable = working very well

my old ralink + all usb cables = working very well


You're falling for the old trap that old worked, why not new. That is, it's beyond the USB spec and as such can be hit or miss. I don't see if you tried an active cable.


A USB cable that is more than 10 feet long (3+ meters) is going to be dicey at best. The fact that it worked with your old WiFi gear was luck. 5 meters (15 feet) is already getting to the limits of the tech for unaugmented (non-active) cables.


thank's guys, what do you advise me with ? any specific type of wifi adapters tha tsupport 10+ cables ? is usb 3 .0 do that ?


Sorry but you were lucky with the first one. It's not the adapter but luck here. Look again at the USB spec then try those active USB cables.

If you are looking at some WiFi client thing you can put away from a PC, maybe Ethernet? Look at what I used last time. The Netgear WNCE2001. There are things like that on Ethernet which can be far away from the PC.


update : i bought the edup ep 8523 and it's working great with 12 meters cables(10meters+2meters) it also come with 5 meters cable included, it's only usb 2.0 .

This topic has been dead for over six months. Start a new discussion instead.
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