13. How to print to a fax machine.

interface efax-0.1 {
   help "This interface uses the efax package's fax program to send a
         fax.  You should first get efax's \"fax send\" working by
         itself by editing the file /etc/efax.rc and testing.  Connect
         this interface to a generic postscript driver to define a
         fax machine \"printer\"". 

   requires { "efax" "fax" }

   # Making phone number required means that the add printer wizard
   # will demand a phone number at add printer time.  This is
   # undesirable, so it isn't explicitly required, even though it is
   # logically required.  The send_exec script checks for the number.
   # You could skip the wizard by adding this printer by hand to
   # .printrc, mark this as required, and it might then prompt?
   argument {
      var = "PHONE_NUMBER"
      desc = "Phone Number"
      help = "The phone number to dial.  Prefixes like 9 ought to be
              defined in your /etc/efax.rc file."
   }

   option {
      var = "RESOLUTION"
      desc = "Fax resolution"
      default_choice = "high"
      choice "low" {
         value = "-l"
         desc = "Low"
         help = "Low resolution on a fax is 96lpi."         
      }
      choice "high" {
         value = ""
         desc = "High"
         help = "High resolution on a fax is 192lpi."         
      }
   }

   # If you don't specify a phone number the job just fails, and 
   # the only way to figure this out is to look at the error message
   # at the bottom of the job details.  Hmm.
   send_exec { 
     if [ "x$PHONE_NUMBER" != "x" ] 
     then
          fax send $RESOLUTION $PHONE_NUMBER $INPUT
     else 
          echo 'You must specify a phone number!'
          false
     fi
   }
}