The situation: Plant operators needed notification and a log of events or alarms happening at a remote pump station, 17 miles away. 

The options:  First, the engineers considered installing dedicated leased phone lines with modems. But when one engineer asked if anybody really remembered or understood the AT codes the modems used (back in the early Internet days), and noone did, they dropped that option. Next, they investigated license-free wireless. That proved impractical: There were hills and valleys between the plant and remote station (no line of sight), and they’d have to lease property between the two locations and install repeater towers at an additional expense.

So, how did they get the data across 17 miles without leasing land or resurrecting obsolete technology? The answer was much simpler and less expensive than they anticipated. Read the rest of this entry »