This is a unit I installed 2 weeks ago at a customer, as they have a lot of power failures. This unit monitor the three phases that goes to the marine section. When there is a failure on phase 1 it will send a sms to the programmed number/s as follows (Phase 1 Failure) and if power is back up it will send (Phase 1 Restored). The cell switch can be adapted to suit your needs as like temp-,water level-, power failure alarms, ect. it can also be used to switch various things on or off. Now my customer knows when a faulty piece of equipment trips the power and can do something about it before there is major losses.
This can be monitored and commands sent with the cheapest cellphone.