The use case is controlling a water pivot (farm equipment in the middle of a field) over an IP network. The equipment is serial on both ends and originally designed to communicate over a phone line but has been used also over priority 900MHz serial equipment.
I am interested in using our IP network to communicate over. I am not worried about any of the network elements like PPTP, EoIP etc, just in using serial on both ends. I need to have a signal created on a serial port on a controller board in the farm house delivered to a serial port on the equipment in the field.
If two Routerboards (RB411 or similar) is not the best solution I would be interested in recommendations.