Your products already support Modbus. Which is an open industrial serial protocol that was first developed in 1979. BACnet can be considered as Modbus's direct replacement. BACnet is also an open industrial serial protocol.
The above shows BACnet as by far and large the most prominent serial protocol for industrial applications in 2018.
Plus there are a number of open source stacks for the protocol available here:
http://bacnet.sourceforge.net/
Tyler
