IBM 1PA, Руководство по эксплуатации, установке и обслуживанию

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– If the polarity is not reversed, contact technical support. For more
information, see Appendix A, “Technical Support.”
Multiplexer Fiber Optic Link Cannot Get “Receive” LED On
A complete fiber optic connection from an upstream Host Multiplexer is required to
switch on the “Receive” LED on each Device Multiplexer. Each Multiplexer is
always transmitting trying to obtain sync over the fiber optic connection. The
“Transmit” LED should be on for all powered-up Multiplexers. Because Multiplexers
are usually located some distance apart, more than one person may be needed to
find a problem in a fiber optic connection.
You must have a complete connection to the Host Multiplexer to switch on the
“Receive” LED in downstream Device Multiplexers. An open circuit anywhere after
the “TX” connector on the Host Multiplexer results in all “Receive” LEDs being off
even if connections from Device Multiplexer to Device Multiplexer are good.
You can test each Multiplexer with a stand-alone fiber optic jumper by setting the
Multiplexer to “Host Multiplexer” The “Receive” LED switches on when you connect
the “TX” to the “RX” connector. Be sure that you set the Device Multiplexer
switches back to “Device Multiplexer” when you restore the fiber optic link.
1. Ensure that the configuration switches are set properly. See “Installing the
7299 Multiplexer” on page 3-5.
2. Ensure that the cable at the “RX” connector(s) of the Device Multiplexer(s) is
connected to the “TX” connector on the upstream Multiplexer and that the
“Transmit” LED is lit on the Host Multiplexer..
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If not properly connected, connect the correct cable.
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If properly connected, go to the next step.
3. Ensure that the maximum cable distance for your configuration is not
exceeded. See Table 2-2 on page 2-8.
Ÿ
If the lengths are too long, consult fiber optic cable installer.
Ÿ
If the lengths are within the specifications, consider that the loss may be
greater than specified and should be measured by your cable installer. If
all specifications are met, contact Technical Support (see Appendix A,
“Technical Support” on page A-1).
Devices Connected Via Multiplexer Get Parity Errors or Terminal
Connections Are Unstable
1. Ensure that all connections (UTP or DB25) to the Host Multiplexer are made
such that one and only one WSC Polling Group (of up to four ports within a
single group) is connected to the “A” (ports 0-3) and “B” (ports 4-7) Sides of the
Multiplexer. If all the connections are not from a single WSC Polling Group, all
Multiplexer ports on the side in question may get parity errors and not be able
to establish or maintain a 5250 session.
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If the connections appear to be from a single WSC Polling Group, go to the
next step.
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If connections are from mixed WSC Polling Groups, change connections to
ensure a single polling group.
Chapter 4. Troubleshooting
4-5