SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

Hello to everyone....I just bought a house that has a RainBird Sprinkler System. I got to inspecting the yard and I found a Green box in the ground (has a green lid) at the back of the property. It has what looks to be a valve of some kind. It is marked RainBird on it but no model numbers. On the side pointing in the direction of the house is connected a PVC pipe. the other end has a normal garden hose attached to it that runs out the side of the green box, and up to the surface and then strung along 3 of my neighbors yards (behind their fence) and then just ends. My question is what is the purpose of that hose? I doubt it was attached by a professional installer. Is that something I can remove and still have the system operate normal? The system is currently not on. I need to have a relative connect the back flow valve onto the house to activate the system and test everything out. The previous owner said the system worked for him fine for 5 years then stopped using it. But did say at closing that 2 of the heads didn't work. I am interested to hear some feedback. Thank you for any help.