If you want to enable Gsky GS-27USB or whatever else external wifi adapter just bought
on ArchLinux just installing the driver rt2870 you will obtain the following error:
The right driver you need to install is the rtl8187se as indicate here.
So you can install it from the AUR and build it as indicate in the wiki or through yaourt sa following:
then just type on the terminal:
to discover the names of your network interfaces, in particular the new one (wwp0s20u4i6 in my case).
Then with wifi-menu you can use the new interface as follow:
That’s all folks!