The system above is a non digital swimming pool control called Easy Touch wireless system with Compool control box. It is a relatively inexpensive way to control a pool/spa combination that is simple to operate no programming involved.
The photo above is a typical non digital control system-in this case,a Chardonnay. These type of controls send signals through the existing home wiring using X-10 type modules. Chardonnay uses 115 volt X-10 modules because they are less expensive than 220 volt X-10 modules,then sends the "on" signal to a high voltage relay that can handle 220 volts and high pump amps. There is some wisdom in doing this to make replacement modules cheaper and easier to find at a local hardware store,but personally,I like having just one high amp module and no extra relay to keep things simple.
The advantage of a systems like these is the lower cost-1/3 to 1/2 the price of a digital system. However,some performance will be traded....for instance:
1)Cannot use the pool controls to power/control a salt chlorine generator.
2)No automatic "cool down" feature for the heater (except Compool/Easy Touch)
3)Cannot use the pool controls to use temperature sensors to turn valves for most efficient use of solar heating
4)Cannot control temperature of heaters remotely
5)Cannot use valves independently to drain spa or have all flow go to spa to create waterfall effect if spa is raised higher than pool.(except the Easy Touch at top of page)
Below is a photo of a Chardonnay valve actuator
So if you do not need all the features of a digital system and/or you are on a budget,these type of relay systems may be for you. They can also easily be custom built for your needs.