Reading Plate Numbers

[additude]

I am pretty new to "serious" collecting of US notes and I can't find an answer to a question and I'm hoping someone can "enlighten" me

 

On the face of most US notes there is the Plate number on the lower right sometimes preceeded with FW, of course meaning printed in Fort Worth, but on the left side of the note there is another small alpha-numeric combination and I can't find anything that tells me what significants it is.

 

I am assuming it's something to do with the treasury seal/serial numbers printing, but I don't know.

 

I hope someone can help me.

 

Thanks,

 

Wes

[Jamericon]

The alpha-numeric pair in the upper left corner of a note are the quadrant numbers. They denote the placement of the note on the printing sheet, whether it be a 12, 18 or 32 subject sheet.