
B-63354EN/04 APPENDIX A.TROUBLESHOOTING
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A.2 CHECKING TRUNK CONNECTIONS
The following does not apply when the network is configured by only a
hub to which the Ethernet board is connected.
The following describes general precautions. Consult a specialist or the
manufacturer when you are building your network. Wire cables away
from sources of electrical noise
• When the trunk is 10BASE-5
1) Make sure that the transceiver is properly mounted on the
trunk.
• If the transceiver is properly connected, the resistance
between the shield and the center conductor of the trunk
is about 25 Ω (when a terminator is connected).
• A special tool for mounting the transceiver is needed.
(Some manufacturers do not provide a special tool. For
details, refer to the Operator's Manual for the respective
transceiver.)
• Do not mount the transceiver at the same location
where a transceiver is already mounted. (Doing so
might damage the cable.)
2) Make sure that an appropriate distance is provided between
transceivers.
• At least 2.5 m must be provided between mounted
transceivers. We recommend mounting transceivers at
intervals of 2.5 m or multiples of 2.5 m. Normally, the
trunk cable is marked with the transceiver mounting
position.
3) Make sure that terminators are mounted on the trunk cable.
• Terminators having a terminal resistance of 50 Ω must
be mounted to both ends of the trunk cable.
4) Make sure that the total length of the trunk cable is within
500 m.
5) Make sure that the transceiver cable connecting the
transceiver and hub is within the specified length.
• Normally, keep transceiver cables to within 50 m.
However, note that the maximum length of transceiver
cables having a small cable diameter is sometimes
shorter than this figure. Check the cable specifications
before use.
• When the trunk is 10BASE-2
1) Make sure that each cable is at least 0.5 m long.
• The minimum interval between nodes (units) on the
network is
0.5 m.
2) Make sure that the total length of the trunk cable is within
185 m.
3) Make sure that terminators are mounted on the trunk cable.
• Terminators having a terminal resistance of 50Ω must
be mounted to both ends of the trunk cable.