IBM 5500 Operational, Installation, And Maintenance Manual page 139

terminal, the terminal addressing, and the terminal termination are okay. Go to
step 2. If the device does not connect, check for problems with the system, the
terminal, the cabling, or the addressing.
Step 2. Attach a balun to the terminal and to the 5500 host port. Use a short
UTP patch cable between the baluns, as shown in Figure 76 . Repeat this step
for every balun and patch cable used.
• If the device connects, the baluns and patch cords are okay. Go to
step 3.
• If the device connects and then disconnects, check for split pairs.
Split pairs use two conductors that are not a twisted pair. If the device
does not connect, check the baluns and the UTP cable for faulty RJ
plug crimping, incorrect plug type, indicating that the cable is not
straight-wired.
Host
Figure 76: Attaching Baluns
Step 3. Use a UTP patch cable to connect the 5500 host balun to the host
input port of the UTP twinax hub (example IBM 7299). Use a patch cable to
connect the terminal balun to the device output port of the UTP twinax hub.
If the device connects, the UTP twinax hub, the pinout, and the polarity
(phase) of all the components are okay. Go to step 4. If the device does not
connect: Check the pinout and polarity of all cables and baluns. The 5500 host
and devices are connected in your configuration, but poor electrical
connections, noise on cables, split pairs, and so on, could be causing errors.
Baluns
Short UTP Patch Cable
Terminal Device
HEX1I016
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