GSM to RS232 Feasibility

My ultimate goal is to establish two way communication between a master RS232 device and multiple RS232 devices using Arduino's and probably cell phones. The reason for coming back to a master RS232 device would be to include the new system in with an older local secure system. I want to be able to send updates from the field devices to the master every 15 minutes and immediately following a status change. The data sent will included 2-3 digital points and 3 analog values. I also want to be able to query each individual field devices from the master at any given time. One other note I will have 120V power at all locations so no need for batteries.

My plan is to break up the project into different steps.

I have the following equipment either purchased or on order. 3x Mega 2560 boards. 3x DFRobot I/O Expansion boards. ( originally planned to use RS485 and still may on some devices) 3x XBEE XSC PRO probably not going to use 3x MAX232 chips

I have been successful in establishing communications between multiple arduino's using the xbee boards.

The next steps that I'm looking into are listed below. 1. Establish two way communication between an Arduino and an RS232 device 2. Establish two way communication from master arduino and field arduino and rs232 device. 3. Purchase Cellular shield and determine whether it would be best to use SMS or some type of direct connection between cell phones. 4. Determine whether it would be better to send data to an external website instead of including data with older isolated system.

Please punch holes in my plan and help me to determine if there is a better approach to this project. I'm not going to say that money is no object because it that were true than I would just go buy a system that would do this but as far as purchasing other equipment that would be needed anything is possible.

Thank you in advance for at least reading my plan!

Sounds interesting :) How far away from the master will the field devices be?


All of our service territory is within a 57 sq mile radius. So it will differ significantly.

I made some progress today. I can now send data back and forth between the usb serial port and other serial ports using the rs232 circuit that I built.

Next step is to actually communicate with the device using the rs232 circuit.