I am working on a project which requires me to work with a RS-485 transceiver and J1708 protocol(for heavy duty vehicles). We found two RS 485 ICs specifically designed for J1708-DS36277 and MAX3444E.The former costs about Rs 118 and the latter costs Rs 630. The one extra feature in the Max IC is +/- 60V fault protection. Can anyone tell me what is fault protection and is it worth spending so much on an IC which has this feature?