Star Trek - Lost Souls [Cortex +]
These structures appear throughout the region where Ocean Grove is located. One has also been found on Equitoria, the island where the dinosaurs live that is the support base for the Unity space Station.
The pillars are roughly twenty-five feet high, fairly smooth construction with a flat top. They have the appearance of cement but the outer covering is actually carbon nanotube construction.
The Mina use the ones in Ocean Grove as an automated communications routing system for their telephone network and to connect their wireless phones to the same network. This is achieved by FM signals, even the routing to the telephone system is done by means of FM.
They use a very primitive manual operator system to connect Ocean Grove to the other cities by means of a network of radio towers.