TRIN Interpretation

[Tim Kruzel <TKruzel@xxxxxxxxxxxxxxxx>]

Is there anyone out there who follows the TRIN indicator who could give
a brief description regarding how to interpret it? Or indicate a place
where one could read about it.

       | Advancing Issues |   | Down Volume |
TRIN = | ---------------- | x | ----------- |
       | Declining Issues |   | Up Volume   |

Suppose one had a large TRIN value. This could come about in two ways.

1) The Down/Up ratio stays around 1.0 but the Advance/Decline ratio is 
   large. One might interpret this as bullish?

2) The Advance/Decline ratio stays around 1.0 but the Down/Up ratio is
   large. One might interpret this as bearish?

It seems to me that TRIN obscures what is happening. Why not follow the
two ratios separately? What am I missing?

Thanks
Regards,
Tim