We are using plugin phonegap: When i send print only get TEST label, but if change language in app PRINTER SETUP (zebra app) to ZPL print OK if print second ticket i get try again TEST label.
 
cordova.plugins.zbtprinter.print("AC:3F:A4:1F:1B:FA", "! U1 setvar \"device.languages\" \"line_print\"\r\nTEXT ***Print test***\r\nPRINT\r\n",
       function(success) {
            alert("Print ok");
       }, function(fail) {
            alert(fail);
       }
  );