Tb5 - twisted-pair bus, 485 - dc-coupled eia-485 – Contemporary Control Systems AI-SRVR Servers to Ethernet Installation Guide User Manual

Page 8

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TD000200-0IH

8

TB5 — Twisted-Pair Bus

The CXB transceiver can be modified to drive a balanced cable system.

This configuration is called TB5 and it supports shielded or unshielded

twisted-pair cable such as Category 5. To support the popular modular

plug connectors, dual RJ-45 jacks replace the single BNC connector.

Follow the connector pin assignments on page 3 when preparing cables

for TB5 use. Wiring between nodes is accomplished in a daisy-chain

fashion with point-to-point cables connecting the various nodes to create

a bus segment. The end device will have one vacant RJ-45 jack to hold

the RJ-45 style 100-ohm terminator required to terminate the bus

segment. Use twisted-pair cable and observe polarity. Modular plugs

must be installed on this cable such that they do not invert the signals.

Do not use cable which does not twist the pairs nor maintain signal

polarity. To test for proper cable connections, hold both ends of the cable

side by side with the RJ-45 plugs facing the same direction. The colour

of the wire in the rightmost position of each plug must be the same if

there is no inversion of the cable. If this is not the case, the cable is

inverted. Up to eight TB5 nodes can attach to one segment which cannot

exceed 400 feet in length. The overall distance of a twisted-pair network

can be extended beyond 400 feet if active hubs are used — providing the

hub ports support the same TB5 interface.

485 — DC-Coupled EIA-485

The 485 model supports DC-coupled EIA-485 communication via a

daughter board that replaces the coaxial hybrid transceiver. This daughter

board receives the conventional P1 and P2 pulses intended for the coaxial

hybrid transceiver and converts them to an elongated P1 pulse (with a

width equal to P1 plus P2) suitable for the EIA-485 differential driver.
One 3-position screw terminal is supplied for either bus or star topologies.

Each segment can be up to 900 feet of Category 5 STP or UTP cable with

as many as 17 nodes on the segment. Make sure the phase integrity of the

wiring remains intact. Refer to page 3 for connector wiring.

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