I need to be able to make configuration changes to a Fisher ROC 503 via the LOI port with a small OIT unit. Due to the location of the units the client does not want his field personnel using a notebook computer so using the Fisher ROCLink program is out. Fisher supports MODBUS RTU on this port. I need the OIT to be suitable for a NEMA 4 environment and would prefer Cl I Div II. If anyone knows of anything available. please let me know.