User's Manual

Models CH45
EIA 422 or 485
2-4
Four Wire EIA 485 Master/Slave
Typical Slave
T+
T-
R+ R-
Master
T+
T-
R+ R-
Last Slave
T+
T-
R+ R-
REP
OFF
REP
OFF
REP
OFF
REP
OFF
2413 2413 2413 2413
Two Wire EIA 485 Master/Slave
21 2121
REP
OFF
REP
OFF
REP
OFF
REP
OFF
21
Master
+
-
Typical Slave
+
-
Last Slave
+
-
Figure 10. EIA 485 Bus Configurations
APPLICATION NOTE
Another variation of the point-to-point concept, is the Optical Star network. This topology
may be created using the DYMEC-DynaStar Optical Star OS5 or OS9. This topology creates a
“Hub and Spoke” configuration which can be useful in solving a network configuration based
upon the physical positioning of the nodes.