Master-Slave Serial Communication in Balanced Twisted Pair Cables

A prototype of serial master slave communication protocol integrated with external failsafe biasing and termination is investigated. American Standard Code for Information Interchange (ASCII) character codes transmitted in balanced twisted pair cable is recorded by using oscilloscope. The main target is to study performance of asynchronous binary code under different lengths in balanced twisted pair cables of master slave serial communication. The findings indicate that the excellence of quality signal transmitted below 60 m length without external failsafe biasing and termination. However, the quality of signal deteriorated significantly as the length further increased from 100m to 1km, significantly improved when external failsafe biasing and termination applied in the balanced twisted cables of RS485 system. Although the changing of cable length significantly deteriorated the form and shape of asynchronous binary code, it does not significantly affect asynchronous binary to be transmitted since magnitude of resonant effect is still lower than the middle bit width used, thereby has not affected the actual data.