Michael wrote Since your original post says you're using the "Ten Ways..." app note already, we need to consider subtleties. .... Unless you have fail-safe biasing on your backbone, that driver needs to always be enabled.
The fail safe bias is in ten ways....
Common mode rejection will depend greatly on the transciever used; however, the ground wire tying all together is an excellent ides if the units are floating. I have seen ground wires melt when two different mains grounds were connected with a #22 wire.

Santanu wrote but some time there is problem in the line garbage data are recieved at the display
That should be rejected by the parity check.

I take it the application is running in an industrial environment and even with twisted pairs shielded or not, noise does occasionally sneak in.

Erik

PS yau are using twisted pairs, I hope.