code: function retrieveWhatAtTransmitter(req, res) {
    if(redirect(req.params.id, '', '', res)) {
      return;
    }
  
    switch(req.accepts(['json', 'html'])) {
      case 'html':
        res.sendFile(path.resolve(__dirname + '/../../web/response.html'));
        break;
      default:
        var options = {
          query: 'receivedBy',
          req: req,
          ids: [req.params.id]
        };
        var rootUrl = req.protocol + '://' + req.get('host');
        var queryPath = req.originalUrl;
        req.barterer.getDevicesState(options, rootUrl, queryPath,
                                     function(response, status) {
          res.status(status).json(response);
        });
        break;
    }
  }
docs: Retrieve what is decoded by a specific receiver device.
  @param {Object} req The HTTP request.
  @param {Object} res The HTTP result.