found this on a raspberry forum.
It's a different manufacturer. The older Edimax EW7811UN is Realtek rtl8188cus (which works with the 8192cu driver). This new dongle has a MediaTek chipset and unluckily there's no driver built in to the stock kernel for that WiFi device. I had a look in the 3.18.1 kernel source tree and there isn't even an unconfigured driver for it.
[www.raspberrypi.org]
It's a different manufacturer. The older Edimax EW7811UN is Realtek rtl8188cus (which works with the 8192cu driver). This new dongle has a MediaTek chipset and unluckily there's no driver built in to the stock kernel for that WiFi device. I had a look in the 3.18.1 kernel source tree and there isn't even an unconfigured driver for it.
[www.raspberrypi.org]