My pool builder's contract included a line item for my system that states "1 Jandy Aqualink PDA^ computer control system". I ended up with an Aqualink RS4 system that I control via my phone app. I also didn't get a Jandy remote/PDA. Two questions: Does the original PDA system allow you to control via the web? Which system would be more expensive, the PDA6 without remote or RS4? I need to add a device to my system but I don't have a spare aux port. Trying to determine should the builder upgrade the RS4 CPU/circuit board at no-cost. Thanks