Authoritarian. Dictatorial. "You will do as you are told with the equipment that you bought from us. And we will limit what you may do with it."
It's a water pump. The signal that I intend to intercept and alter comes from the pump through a communications unit that connects to the web through a GSM module. One can change settings on the pump through this comms module (via bt or web) as well as get updates on current working pressure, pump motor rpms, etc. I intend to cut into this link where the comms module links with the GSM module, i.e. RS485.
My immediate question is, and I'm yet to open up the box and start cutting into wires, is it possible to simply monitor normal communication between the comms module and GSM module without altering their normal communication? I need to observe at first to see if there is any encryption involved, and what protocol is used before I go further. Ideally I would like to set up an Arduino with SD data logger to grab normal comms so I can analyze it.
Once this is done and it is not encrypted, and I'm able to alter the data, then I'd like to start playing around with sending the data to my own server and unlock the full potential.
How do I listen to the normal "conversation"?
The GSM module used in this unit is:
(the RS485 model, not RS232)