Physical Links
RS 232 is peer to peer connection RS –stands for recommended standard RS232-fullduplex 3 wire (transx,recievx,signal ground) It support one master one slave Its work like hand shaking principle(send & receive alternatively) It communicate up to 15mts RS422 is extension of RS232 Full duplex 4 wire (T+, T-, R+, and R-) It support (communicate)upto 10 devices It communicate up to 1200mts RS 485 half duplex 2 wire (D+, D-) It support up to 31 devices It communicate up to 1200mts