MIDAC is an acronym created in 1981 by a Sydney-based business, Combined Resources Computing (CRC). It stands for Microprocessor Intelligent Data Acquisition and Control. CRC was established in order to complete several building automation projects commenced by R-Tec. R-Tec was an Australian development company based in Sydney that focussed on designing innovative computerised building automation products. The proprietors formed R-Tec in the late 1970s after leaving Johnson Controls. The early R-Tec automation systems used TTL logic with control parameters stored in dynamic memory. The early computerised building automation systems or BAS monitored alarms and conditions relating to building services including air conditioning, water and power, etc. They also controlled plant by starting and stopping pumps and fans according to time and other interlock conditions. The systems of the 1970s and early 1980s used parallel or multiple conductor communications data busses to communication with Data Gathering Panels (DGPs) located throughout the building. The DGPs would communicate monitored conditions using multiplex techniques back to a central location and "front end" system through the parallel data trunk. In the same way commands to start and stop plant would be sent from the front end to the DGP and then to the machine. All decisions or "intelligence" was centrally located, and the DGPs simply relayed information. Combined Resources Computing was established by Kevin Johnson-Bade, an ex R-Tec software engineer, with the prime goal of completing the building automation system contracted to R-Tec by the University of Melbourne. This occurred when R-Tec closed down, being unable to complete its contractual commitments. The University of Melbourne building automation system was ambitious. In 1982 it was possibly the first successful implementation of a distributed intelligence building automation or Direct Digital Control or DDC system using Z80 microprocessors. Remote units called Satellite Intelligence Units (SIUs) were located in buildings around the campus and were connected to the front end using a serial communications. See: Distributed control system CRC developed a unique object-oriented control algorithm building approach. Even though the Z80 microprocessor of the time ran at only 1 MHz, and had a memory addressing range of 64 Kbytes, the University of Melbourne system out-performed other automations systems of the time significantly. CRC created a front-end computer that used ten processors to share the task, having access to up to 256 pages of shared memory. Each SIU used two Z80 processors. This allowed the intelligence to be shared, and