ho made the c-o-two fire extinguisher pdc-20?

Answer 1

The manufactuer's name is usually on the band. PDC as a model number usually referes to dry-chemical however and not CO2.

http://www.wfrfire.com/website/front/index.htm?/website/interior/exting/bicarb.htm&front

Take the unit into a fire extinguisher service company. It's never a bad idea to have the unit checked annually anyway, and they can probably tell you who made it.

Look up fire extinguishers in the yellow pages for a service company near you.