AT&T 3B2 Maintenance Reference Manual page 265

Feature Cards
Figure 8-13. Network access unit (NAU) card CM195U
The following procedures help to determine if an NAU card is defective, but they will not help
locate a problem with the network to which the 3B2 computer is connected.
The diagnostics supplied with the software should be used to troubleshoot problems with the
NAU. If there is a question as to whether the problem lies with the NAU or with the network,
completely disconnect the NAU from the network. Then, run diagnostics. For disconnect
procedures, see the installation guide provided with the NAU.
Ensure that the STARLAN cable is disconnected at the NAU jacks. The jacks loop-around
automatically when a cable is not plugged in so that the external diagnostics work. If the
diagnostics pass with this configuration, connect the NAU to the network and run the external
diagnostics again. If the diagnostics fail, the problem lies elsewhere in the network. Refer to
the STARLAN User's Manual for information about troubleshooting network problems.
NOTE: When you are connected to the AT&T STARLAN network, the network must be
operational for diagnostics to pass.
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