RS485 is a multi-drop half-duplex data bus topology where only one node can transmit data and all the other nodes should receive at a given time. Because of the half duplex nature of RS485, transceivers at each node must be properly switched between transmit and receive modes during data transmission and reception respectively. Since usually there is no flow control signal lines for RS485 and RS422, direction control switching for the transceivers becomes even more complicated.
Teherefore, the real solution to the problem should be an intelligent one wihich follows transmitted data at the input side and switches the transceiver respectively.
Semi-automatic repeaters contain a control circuit for this purpose. However, timing for switching the transceiver between transmit and receive modes is strongly dependent on the data rate and data format (bit length) being used. This is why the control circuits of semi-automatic convertors require complicated DIP switch combination set-up procedures in order to match the data rate and the data format being used.
"Self-Tuner" is a patented technology solution to this problem where no DIP switch set-up is needed. Using the RS422 / RS485 repeaters containing "Self-Tuner" ASIC chips, you only require to connect the signal lines at both sides and notihng else. Both RS485 transceivers at the input and output of the repeater will be properly switched between transmit and receive modes by automatically adapting to the data rate and data format being used and an excellent and error-free communicaiton will be performed.