Having got as far as having the correct sequence of characters to open the drawer, it was just a case of how to send a file directly from the web server to the printer (without IE corrupting it). We have a captive audience, so we have the luxury of being able to fiddle with OS settings. I personally have the added advantage of sitting across the room from Brian so I know this works :) Assuming a Windows 2000 environment with the printer set to be the default, here's what to do:

1. Put the binary file containing the control chars under the page root somewhere. Give it a .till extension.
2. On the client PC, create the file c:\snozone\print.bat with the contents:

   copy %1 lpt1

3. On the client PC, associate .TILL files with the batch file. To be pedantic:
   • In Windows Explorer, click on Tools -> Folder Options...
   • Click on the "File Types" tab
   • Click "New"
   • Type .TILL as the file extension then click "OK"
   • This should appear in the list of registered file types and should be highlighted.
   • Click "Advanced"
   • At the top, change the name from FT00000n to TillDrawerOpener
   • Untick "Confirm open after download"
   • Click "New..."
   • Enter Print as the action
   • Enter c:\pathtofileyoucreated\print.bat "%1" as the application used to perform action
4. Say the magic words "Open sesame" while requesting the file in IE. You should very briefly see the download dialogue and a command prompt flash on the screen, and the till drawer will open.
5. It's easy enough to call this from JavaScript in a new window or a hidden frame.