Why RS-485 cable uses daisy chain configuration rather than star topology to connect equipment?
Star topology will have reflection signals, thus affecting RS-485 communication. Distance between main terminal to destination devices should be kept short; no longer than 5m. If termination is not properly done at each branch line, there will be reflection signals which will cause strong interference to communication, therefore have to eliminate this from happen. There are 2 places that use RS-485 line within Smartkey Access Controller. One is from PC to controller and the other one is from controller to its connected RS_485 readers. 6. Can there be a contact point between equipment on RS-485 connection? Use same cable within the same network system to minimize the contact point on the line. Make sure the contact point is properly attached, tightly wrapped, avoid loose and oxidation. Ensure that a single, continuous signal path as the main bus line. 7. What is common mode interference and differential mode interference? How to eliminate the communications interference? RS-485 communic
