Instructions

Tips & Tricks
© KUNBUS 79
10.3 Use of stub lines
When speaking about stub lines, one must distinguish between
active and passive stub lines. Active stub lines can be, e.g.
repeaters or optical couplers. They do not have any negative
influence on the signal quality of the bus. Passive stub lines,
however, (e.g. bus terminals or simple cable stubs), have to be
avoided in every case. In general, it is claimed that with low
baud rates (< 500 Kbit/s) no or only minor reflections occur,
however, this does not comply with the reality. The reflections
are there, even if they might not affect the data traffic with low
baud rates, as there is enough time for the signal to transiently
match the corresponding value.