Physical layer interface standards(RS232,RS449,USB)

  • www.libary.ncsu.edu.edu/marion/ANX-7852

  • www.diffuse.org/api.html

  • www.library.ncsu.edu/marion/ANX-7852

  • www.frforum.com/5000/Approved/FRF.4/OLD/FRF4.3.1.html

  • www.cell.onecall.net/mhonarc/cell-relay/1995Dec/msg00197.html

  • www.ece.wpi.edu/courses/ee535/hwk7cd95/bkh/physical.html