With one exception, each field bus driver (network) associates with only one physical communications port on the host platform, and uses a specific communications protocol. The exception is the BACnet driver (BacnetNetwork), where multiple ports (Ethernet, RS-485 for MS/TP) and protocol variants (BACnet-Ethernet, BACnet-IP, BACnet-MS/TP) may be used. See the Bacnet Guide for details.

Generally, field bus drivers can be categorized as one of the following: