DATA AUTONOMOUS TRANSMISSION:

This could be the possible replacement for the ARINC 429 standard and will be annotated the standard - ARINC 629. In the DATAC system, the control function is distributed among all the participating terminals present on the bus. These terminals autonomously determine the transmission of data on the bus by means of a protocol termed Carrier Sense/Multiple Access-Clash Avoidance (CS/MA-CA). In simple terms the protocol guarantees access to any participating terminal, but prevents any terminal from access to the bus before all other terminals have had an opportunity to transmit data.

Data transmission by DATAC comprises strings of data words accompanied by a label and address data. The data length is 16 bits as for Mil Std 1553B, however DATAC offers more flexibility in terms of the number of terminals; 120 terminals may be supported in lieu of the maximum 31 offered by Mil Std 1553B.

DATAC will use serial Manchester bi-phase, 1 - 2 MHz data transmission over twisted wire. Note; The 629 data bus is an unscreened cable.