here's mine on a pole, but if I were running this outside of a building, I'd do something similar. Looks like an electrical outlet. This comes up from underground from the garage. Those guys who cringe about using plastic pipe for air, look away now.
That is basically what I did. My reel is a few feet from the door. If you have a coupler outside, you still have to drag a hose out to plug into it. I figured it was just as easy to drag the hose off the reel, and then wind it back up. I use the air outside quite often to blow the dirt of my mowing tractors.I have made this recomendation to several friends that have plumed their shop
the other option (what I am doing) is to have a hose reel right by the garage door (hanging between the door and the side wall) for easy access to pull out
bob