Need Help Rooting Unknown Android Phone

[nipian]

Recently I bought this Android phone. The type is Nexian NX-A891. It's a dual sim Android phone.
But, this phone doesn't include USB driver in its box.
So, I tried to root this phone using Linux.

In the terminal, I type lsusb and one of the output includes 1d91:0016 that I believe indicating this phone, but without name or identity of this phone on the output.
Then I edit the udev 51-android.rules, insert idVendor=1d91, restart udev, and type adb devices.
But why is the output is just a blank "List of devices attached"?

Anyone can help?
Thank you so much.

 

[gta]

pls tell the specs of phone nd company pls in india we hv a phn with same id i.e 1d91

 

[nipian]

pls tell the specs of phone nd company pls in india we hv a phn with same id i.e 1d91

it has:
- dual sim (WCDMA/GSM)
- 3.2 inch 320x480 display
- android 2.2.2
- CPU ARMv6 600MHz
- dual camera (3.0 mp rear camera and vga front camera)

the company is nexian.
and from what i have heard is that nexian is now cooperate with spice (isn't this indian company?)

thanks.