TDMA process

The fundamental difference between byteflight and CAN, apart from the different transmission media, is in the manner in which the bus is accessed. In byteflight this is done through the so-called Time-Division-Multiple-Access process (TDMA). This means that there are time slots set on the bus within which a definite message may be transmitted. (This type process is also used in the GSM mobile telephone system.) The TDMA process requires a very precisely timed synchronisation of all the bus devices. This is guaranteed since the bus device cyclically transmits a so-called synchronisation pulse, SYNC pulse, to the bus. The time interval between these synchronisation pulses is divided into

• a number of time slots for "very important" messages which are transmitted in each cycle (high priority, synchronous messages) and
• a remaining time range for transmitting not so important messages, which are only sent occasionally (low priority, asynchronous messages).