Page A-3
Manual 00650-519-1
RS485 Two-Wire Multidrop Network
The following illustration shows a typical multidrop or party line network. Note that the
transmission line is terminated on both ends of the line but not at drop points in the middle of the
line.
Figure A-1:
Typical RS485 Two-Wire Multidrop Network
RS485 Four-Wire Multidrop Network
An RS485 network can also be connected in a four-wire mode. In a four-wire network it's
necessary that one node be a master node and all others be slaves. The network is connected so
that the master communicates to all slaves and all slaves communicate only with the master. This
has advantages in equipment that uses mixed protocol communications. Since the slave nodes
never listen to another slave's response to the master, a slave node cannot reply incorrectly.
