Communications within building environments have traditionally been served by serial communication systems
that have been efficient and cost-sensitive. Serial communications technology is established and
cheap to incorporate within controllers and devices in a highly competitive building controls industry.
Using serial signalling technologies such as
RS-422 and
RS-485
are commonplace, however each manufacture has its own way of framing the data bits.
Controls manufacturers have a reputation for protecting their product base and tying in the building
owners to proprietary control communications protocols. With this in mind, a number of control
communications protocols have been developed that have attempted to be more open in the way that
they operate. The theory being to allow multiple vendor interaction provided that certain
compliance criteria are met.
