Device Object Technology (DOT) enables information from one device to be interpreted by another without prior knowledge of the device itself. Interoperability between devices is achieved through:

Interaction between devices is built upon natural language to describe the objects, their methods and their operators. This is the opposite way round from the fieldbus approach in which codes are prescribed for each of these functions.

An advantage of DOT is that a designer of a new device can innovate without reference to pre-existing Standardised functions. The new functions themselves can be 'inventions' peculiar to the device because, through object-names extracted from the device, object functions can be interpreted and used.

Messaging
The human mind can interpret and use the objects directly through a device-object-browser (analogous to a web browser).

Devices can do the same if programmed to look for a particular function name. Once devices have identified the full object name in this way, natural language can be replaced by shorthand coded language for all subsequent interactions. The codes reside in the device and do not need to be explicitly defined by a Standard. It is the words themselves describing the objects in natural language (TEMPERATURE, PRESSURE, UNCERTAINTY., READ:, DO: ... etc.) that need explicit definition for interoperable use. This is a task for a Standard committee. On the other hand, proprietary objects, also accessible by an Object Browser, need not be Standard objects because interoperability is not required of them (for example SETPOINT_T6).

Communications
To avoid entanglement with a communications technology, DOT must have its own physical interface through which messages pass to a transceiver designed to do the talking (IEC1158, IRDA, CAN, Bluetooth etc.). The interface needs to be simple, fast and low cost. SPI is a natural choice at this time.

Hymetrics have used the SPI interface of IEEE1451.2 called the TII (Transducer Independent Interface). This provides the connection to a transceiver designed communicate using one of the several communication options (CAN, Ethernet .... etc.) The communication protocol can be handled by a dedicated processor on the transceiver or by a task to be executed by the device's processor.

However this is implemented, the separation of communication activity from device function is a vital principal of design. Failure to do this locks the development of a sensor for example, into one style of communication foregoing all other possibilities.

Modular construction
Thus DOT devices are modular in the sense that the designer creates the device without consideration of the communication means and communication protocol. The installer can select the communication tranceiver to suit the requirements on site.

The Object interface is also modular in the sense that the designer can add objects to a standard product to extend its scope of operation: for example, objects for: data recording, self-calibration, estimating measurement uncertainty ... etc.