Zodiac Jandy iAquaLink 2.0 Wireless Network Pool Control Interface Sys. | IQ20-A Upgrage for Aqualink - RS rev. R and later, PDA rev. 6.0 and later, Z4 all For older systems you will need the PCB upgrade. Seamless addition to any AquaLink system, one of the most trusted name in pool controls. Allows you to turn the spa on while you"re away, so it"s hot and running by the time they get home. Allows you to turn the spa on while you"re away, so it"s hot and running by the time they get home.