IBM 5500 Operational, Installation, And Maintenance Manual page 122

122
Chapter 6: Twinax Client Cabling Requirements and Problem Solving
The bumps at 1.3 and 2.5 indicate workstation connectors. The large bump at
2.5 indicates a larger mismatch (poor connection) than at 1.3.
0.2 V
A=20 µs
B=0.2 µs
Figure 54: Open Cable
Figure 55 is not a correct display of cable reflections. The multiple reflections
are at 26 m (85 ft) of a good cable with an open end. This display is caused by
the wrong vertical gain setting (0.5 V/div) and the wrong B-time/div. Only the
first reflection in this figure is important and should be magnified by changing
the vertical gain to 0.2 V/div and B-time to 0.05 µs/div.
0.5 V
A=20 µs
B=0.1 µs
Figure 55: Open Cable (Wrong Oscilloscope Setting)
Figure 56 shows a 155-m (510 ft) cable with one wire shorted to shield at
approximately 78 m (255 ft). The end is left open. This scope figure is valid
for the twinax cable only.
Planning, Installation, and Maintenance Guide
1.3 2.5
Open
Multiple Reflections
0
Open
55E1I031
55E1I032