On a good day, I learn something new..
I did not know (or had forgotten) that old style spinning disc meters could be read remotely.
Called Automated Meter Reading (AMR). Then, I found this page.
http://www.highelectricbill.com/ElectricMeters.htm
Yours must be like the one on the bottom of the page.
It has a spinner and it also has the electronics to read and transmit power data..
My guess is, they have an optical sensor watching the disc spin.
But, it's not so smart that it knows which way the disc is spinning..
Whereas those old mechanical pointers will turn backwards,
hence the honorable practice of reading the dials at the net-metering change over.
It's been so rainy and/or overcast for so long around here, I'm starting to forget my Enphase dreams.
Even my little solar powered entry lamps are in hibernation now. ;(
Cheers,
Rich