Rastertocard filter

[shermin]

Hi,
I am developing my filter for my card printer.My printer cmd is actually based on usb mass storage device,Sending the cmd thru "CBW" and read the status through "CSW".But in standard filters coming with CUPS commands are send using printf.In my case if i use "usb_bulk_write" whether my filter will work.??How will i map it to "printf" in cupsd.
Or if i use putchar a,how will i read the status from the printer?????

Plz help
Shermin