def is_connected
      res = Nfc.tech_is_connected(@techname)
      resb = false
      if res != 0
          resb = true
      end    
      return resb
  end
def is_connected
      res = Nfc.tech_is_connected(@techname)
      resb = false
      if res != 0
          resb = true
      end    
      return resb
  end
return true if tech connected and ready for I/O operations