The send and receive SMS feature allows to send SMS (Short Message Service) messages directly from WinCC OA as well as to receive them in WinCC OA. You can send SMS messages from WinCC OA to a GSM (Global System for Mobile Communications) cell phone via a cell phone or a GSM modem as well as from a cell phone or a modem to WinCC OA. For more information see chapter Send and receive SMS messages, basics.