Contemporary Control Systems AI-USB Adapters - Manual (Page 8)

TD030500-0IB
8
CXS Coaxial Star
There are generally two types of coaxial cables that are used
with ARCNET, RG-59/u and RG-62/u. RG-59/u is 75-ohm
cable which does not match the impedance of the transceivers
used on the AI ports. This cable will work, but communication
distances are reduced compared to RG-62/u because of the
higher attenuation of RG-59/u cable. We recommend RG-62/u
because it is a better match to the transceivers and a full 2000
foot segment distance can be achieved using this cable. Both
cables support male BNC connectors which the CXS port
accommodates. When connecting to a CXS port, do not apply
a terminator or BNC “T” connector to the port. Simply connect
the coaxial cable directly to the BNC port.
Figure 12 — Typical Connections for the AI-USB/CXS
TB5 Twisted-pair Bus
The TB5 transceiver accommodates twisted-pair cabling via a
pair of RJ-45 jacks. This option allows the insertion of a hub at
any point along a bus segment. Usually IBM type 3 unshielded
twisted-pair cable (UTP) is used, although shielded cable can
be used as well. End devices require a passive terminator that
matches the impedance of the cable (typically 100 ohms).
The dual connectors allows daisy-chaining of the hub 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 to match the cable impedance
is required at the unused jack. For this purpose, a 100-ohm
terminator in an RJ-45 module (part number TB5-TER) is
supplied with the hub.