It is not wifi that's for sure...I actually own one of the older devices that I have seen in your pictures and you still call them Wi-fil....but they weren't!
I've always wondered as well, I've seen a bunch of these up in CT. I think they may be used for emergency services such as police or fire but I'm not sure.
The older ones are wirefree systems....but not this one....this one is newer and wirefree systems are outdated and bankrupt...
But the newer stuff, not sure if this one is it, but I know another model/make that is similar to this but different that are for the smart meters..... In here PEPCO powers and uses smart meter wireless systems mostly on their streetlight photocell receptacles to get power from.....BGE uses same models as PEPCO but does not attach the, directly on streetlights but wires them directly to the transformer and uses a short arm alone....
But the newer stuff, not sure if this one is it, but I know another model/make that is similar to this but different that are for the smart meters..... In here PEPCO powers and uses smart meter wireless systems mostly on their streetlight photocell receptacles to get power from.....BGE uses same models as PEPCO but does not attach the, directly on streetlights but wires them directly to the transformer and uses a short arm alone....