VVTC... how does it work

[Jeff240sx]

I am looking at a s15 sr20det engine and understand how most of it works.  I just don't know what vvtc is.  I know after Honda let out VTEC, with 3 cam lobes, and then toyota and Porsche come out with variable valve timing methods.
I just wanna know how Nissan's VVTC works.
Thanks,
-Jeff

The i-VTEC system combines VTEC (Variable Valve Timing and Lift Electronic Control) technology with an innovative new camshaft phase control system called VTC (Variable Timing Control).

VTC uses a spool valve that directs high-pressure oil to chambers inside the intake cam's drive sprocket that allows for continuous adjustment of the intake camshaft's phase (position relative to the crankshaft) over a range of +/- 25 degrees (advance or retard). A separate VTC electronic control unit monitors RPM, camshaft and throttle position, ignition timing and engine exhaust condition to determine the necessary cam phase adjustments.

thats honda style. i guess its the same style with nissan