reading data from raw printer

[Moritz von Schweinitz]

Hello,

I'm using cups (with a lot of success) to drive a lot of point-of-sale printers (Epson TMU-200) using the raw-text mode. I open the attached cash-drawers sending binary commands to the printer.
I was asked whether i can implement the option that the point-of-sale software 'blocks' for as long as the cash-drawer is open. These cash-drawers are usually connected to printers, and when sending a special command to the printer, the printer sends back a status code that indicates whether the cash-drawer is open or closed, and this is relatvely easy to implement when talking directly to the serial port.
But i'd like to do this over cups. Is this possible? Something ins the spirit of:
$open = `echo $send_status_command | cups -P tmu200`
?

How can i read information from a printer?
Thanks for any help,

Moritz von Schweinitz