Black Box BRI-HUB ISU2011-4-EURO User Manual
Page 11
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BRI-Hub
TECHNICAL: 0118 931 2233
The TE-ports termination resistors are permanently active and cannot be switched off.
Please install terminating resistors to the end of the connecting cables.
In the above example the Term-switch must be in the off position, i.e. termination resistors
are off. This is because the BRI-Hub is not connected to the end of the bus.
Power Failure Operation
If the BRI-Hub loses power, the terminal devices directly connected to the NT ports will still
operate. For this to happen case one must observe the maximum cable length and the position
of the terminating resistors. In more detail this is:
•
The length of the cable connecting the NT to the BRI-Hub plus the length of the cable
connecting the BRI-Hub to the TE on the second NT port must not be longer than 150m.
Both cables form a passive bus.
•
In case of a bus installation at the NT port, BRI-Hub must be the last device on the bus.
•
The termination resistors must be switched off. Termination resistors must be installed at
the end of the TE’s bus