I assume that you have already two wires (one pair) from end to end. which BSNL/VSNL provides.
In your case, i believe both location falls in same exchange, so it will be with minimal cost.
couldnt able to find manuals abt your device.
But it has web-based gui as well as CLI .
For CLI u can connect it in Hyper Terminal via RS-232.
Default setting should be 9600, 8, none, 1, None.
i would definitely try to help further if you stuck anywhere .
Thanx