“PrintExtra” - an InSight client that adds additional print lines
at the end of the receipt of certain transactions. At
initialization, PrintExtra establishes a printer DataWatch for the
paper cut command and indicates to automatically enable filter
control mode for the printer. When the terminal agent sees a paper
cut command and sees it is in a DataWatch list, the terminal agent
intercepts the printer i/o request containing the paper cut and
forwards it to PrintExtra. PrintExtra now owns the i/o request and
must respond with a possibly modified request. Once the terminal
agent request is returned, it is passed down to the 4690 printer
driver.
“VoidWatch” - an InSight client that looks for use of the ‘void’
function code and repositions a camera to the lane doing the void.
Because it takes time to reposition the camera, the application
wishes to delay the sales application until the camera is ready. At
initialization, VoidWatch establishes is keyboard function code
DataWatch for the void function code and indicates to automatically
enable filter control mode for the keyboard. When the void key is
pressed, the i/o request containing the void is forwarded to
VoidWatch, which positions the camera and returns the i/o request
unchanged.