How can we help you with BACnet ?




There is too much to fit on one page – Please choose your area of interest.


Free Explorer and Guide

When you purchase a gateway from CAS which includes a BACnet driver then we include a full license to the CAS BACnet Explorer. You can use the explorer to test / prove / document the BACnet interface. Some limitations apply to this offer and it is a limited time offer. Read more about the CAS Banet Eexplorer.

You can purchase this guide for $20 from or download the BACnet For Field Technicians for free.


BACnet Arcnet

Uses the legacy ARCnet physical networking layer. It is not compatible with Ethernet Networks. It is difficult to debug/troubleshoort unless you have ARCnet tools. ARCnet provides peer to peer networking in a star topology. Only some FieldServer’s support this technology as it requires an ARCnet network adapter.

BACnet Ethernet

This is the legacy Ethernet option predating the IP option. This version of BACnet uses the Ethernet Physical Layer and the 802.3 Ethernet Protocol to carry data. Broadcasts are always global.


Most newer devices use this flavour of BACnet. It uses the Ethernet physical layer and carries its payload in the IP portion of the Ethernet packet. Discovery broadcasts are typically only on the local subnet. A technology called BBMD allows devices on remote subnets to be discovered.


This flavor of BACNet is typically used to connect field devices such as thermostats. It uses the RS485 physical layer and as such can carry up to 128 devices per trunk and run to a max of about 4000ft. The devices are connected sequetially on a trunk but all master devices are peers of each other. Often repeaters are used to extend the length of the line. Surge protection, termination, grounding and quality of installtion can be important issues.

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