How can I switch from 10 cpi to 17cpi and back without using PCL codes.

I have a Dell S2500 printer.  I am working in an environment where I can not use the windows print drivers or PCL codes.  I need to make the printer print in condensed mode for some reports and 10 cpi for others.  Where can I find the codes needed to change from 10 to 17 cpi and back to 10.  They string I am looking for would normally start with a Char(27) followed by the required string of characters.