Siemens M20T operational

Today i finished the interface for my Siemens M20T. This interface handles all the low-level communication with the M20T:

  • Initialization at startup for things like PIN code, Echo setting, SMS mode;
  • Sending SMS;
  • Receiving SMS notifications and reading the SMS;
  • Deleting read SMS message from the message store.

The class i created for handling the communication with the M20T was derived from a special ‘Physical Interface’ class i created a long time ago when i was developing the basics for my Home Automation system. All classes that interface with hardware, whether it is PLCBUS, RFXCOM, X-10 or whatever, are derived from that class. That way i only have to develop the device-specific routines and when that part is finished, the new hardware is instantly and completely integrated with the rest of my system:


No need to do additional development to enable an SMS to trigger an event, store historical data in the database, or to have the information available in my Home Automation GUI that’s running on my ASUS TOP in the living room. It’s just like writing a HS Plugin 🙂 Last month i developed 2 new interfaces for new hardware this way.

The Siemens M20T will be moved to the place where lots of other Domotica hardware can be found, the fuse cabinet. There it will be attached to a Sollae EZL-400S, and occupy it’s 3rd port. The first 2 ports are going to be used by my X10 interface and my PLCBUS interface. Those last 2 interfaces are currently connected to 2 single port serial to Ethernet converters, but by connecting these 3 devices to a single multi-port serial to Ethernet converter i can save additional power usage.

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