If something can be turned on or off with a switch then we can design and install a system that can remotely control that function, or better still, automate that function. It is not necessary to be waisting your time as well as money on fuel driving to locations just to flick a switch at a remote location. Couldn't your time be better spent doing something much more productive than that?
A simple example is where you have a water tank that needs to be filled by turning on a pump. A simple telemetry system can be installed using a sensor in the tank that detects when the tank is below a preset level. It then wirelessly transmits a signal to a controller connected to a pump, thus turning a pump on. The pump will continue to operate until such time a preset fill level is reached where the pump will be automatically shut off. In the event the pump is not shut off after a preset time the system is configured to automatically turn the pump off and send an alarm indication.
In the above example we used basic digital logic, a 1 and 0 or an ON or OFF state to send signals from a level sensor to a pump controller. We can also use analogue signals such as those from 4~20mA current loops, which is very common for sensor outputs. An example is where you have a rather expensive pump and in the event of low flow or low or high pressure the pump must be shutdown to prevent equipment damage. Implementing flow and pressure sensors with 4~20mA outputs you can monitor the pipe flow rate and pressure at a strategic location. In the event the flow or pressure go outside preset parameters a signal can be sent wirelessly to the pump controller to shut the pump off. An alarm signal can also be sent so as to alert someone that a fault condition exists.
These are just two simple examples of using basic telemetry systems to control and automate a simple process, from automatically turning a pump on or off to monitoring flow or pressure from the pump to protect it from damage. There are far too many cases to list here for using a wireless telemetry system and they also integrate with network connections forming robust monitoring and control networks.