You'll see more of these pots on poles in rural Oahu areas.
By Ken Sakamoto, Star-Bulletin

It is, obviously, a pot on a pole. More specifically, it's a thing that looks like a big rice cooker attached to a telephone pole, and even has a caution plate, warning users to release the 15 PSIG pressure before opening the pot.

The one shown here is on Sunset Avenue near Leahi Hospital. You're more likely to see them in rural settings, however.

What they are is food-distribution containers for the homeless. No, not really. At least one Star-Bulletin copy editor almost fell for that one, though.

They are "repeater" boosters for telephone signals. According to Calvin Tadaki, Hawaiian Telephone spokesman, as a phone circuit gets farther from the central switchboards, more resistance builds up on the long line, and it takes more juice to get the signal through.

Which explains the countryside pole pots. In town, however, an older neighborhood like Kaimuki had perfectly adequate phone lines originally, but during the years, more lines were added, signal quality became more important to finicky subscribers, and additional devices like computer modems added to the drain. So, pole pots to the rescue.

And it's pressurized to keep rainwater out. Most phone company equipment, in fact, is under pressure, pumped up from within the phone lines themselves so that they stay dry. In other words, the pole pot is sealed with a hiss.