Thank you all guys (Mr. Karas, Mr. Erik and MR. Neary)

Thanks for the suggestions as i have already informed u guys that i have followed the "ten ways to bulletproof RS485" i also have taken one ground wire along with the rs485 line (CAT 5 cable) basically i am using two TP for rs 485 signals i.e



and following is biasing with 1K-100E-1K



I liked the idea of erick about parity check, do u think that will help me. What eaxctly is happning is after few valid transmission ther is some garbage data over few displays at random

Thanks Santanu