Well, you are talking about two different systems. They are NOT the same system.
If you have a standard install for Wamp, you have an Apache based server running for an example.
But, both will use your current default Windows printer setup. This is what PDFtoPRINTER.exe’s site says:
Duplex printing: PDF-XChange Viewer cannot save a duplex-printing option as the default. To print in duplex mode, modify the settings of your Windows printer (in the Windows Control Panel or Settings app) to enable duplex printing, or create a duplicate copy of your Windows printer, set it to print in duplex by default, and specify that printer when running PDFtoPrinter.exe. Search the web if you don’t know how to create a duplicate copy of your Windows printer or if you don’t know how to specify duplex printing in your Windows printer properties.
So, are you testing as a website or or just using Wamp to let you run PHP code locally? Wamp is a complete emulator of a website server with PHP installed on it. If you are using the PHP to just print items, you can have the line printer option send the PDF file to the printer. The defaul setting inside the printer must be set to duplex mode. Something loosely like this should work:
shell_exec(’/usr/bin/lp -P “C:\Wamp\www\upload” . $file);
It doesn’t use the outside executable program, but just sends the file to the printer. Might work…
On further research for you, if you use the shell-exec to call an .exe file, you need to escape each backslash you have in the command. So, try this and see if it works:
$output = shell_exec(‘C:\PDFtoPrinter\PDFtoPRINTER.exe C:\Wamp\www\upload\’.$file;
This might work, too…