Contemporary Control Systems AI Active Hubs - Manual (Page 25)

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2.6.7 Connecting Shielded Twisted-Pair Bus Networks via
RJ-45 Connectors (-TB5)
Some AI3 models support twisted-pair bus operation via dual
connectors. This allows insertion of the AI at any location on
the bus segment and provides continuous shielding between
devices. When the TB5 port is located at the end of a bus
segment, passive termination is required at the unused jack to
match the cable impedance (typically 100 ohms). Refer to
Figure 2-15 for the RJ-45 connector pin assignments.
Figure 2-15. RJ-45 Connector Pin Assignments
2.7 Variable Data Rates
Newer ARCNET controller chips support variable data rates up
to 10 Mbps. However, transceivers such as -CXS, -CXB and
-TPB will only operate at 2.5 Mbps. On these AI models there
are no provisions for variable data rates as evidenced by the
lack of a data rate switch. On all other models, a data rate
switch is present which must be set to the correct speed of the
network. A table has been provided to aid in setting the 8
position switch. Switch positions are labeled 0-7 with position 6
further identified by a dot indicating the 2.5 Mbps default
position. A clockwise rotation increases the data rate setting.
Use the following table to set the data rate: