netsys NH-300SP User Manual page 25

NH-300SP 2Ethernet HPNA Modem USER'S MANUAL Ver. A.7
System Diagnostics
Power and Cooling Problems
If the POWER indicator does not turn on when the power cord is plugged in, you may have a problem with the power
outlet, power cord, or internal power supply as explained in the previous section. However, if the unit power is off after
running for a while, check for loose power connections, power losses or surges at the power outlet, and verify that the
fan on back of the unit is unobstructed and running prior to shutdown. If you still cannot isolate the problem, then the
internal power supply may be defective. In this case, please contact your local dealer.
Installation
Verify that all system components have been properly installed. If one or more components appear to be
malfunctioning (e.g., the power cord or network cabling), test them in an alternate environment where you are sure
that all the other components are functioning properly.
Transmission Mode
The default method of selecting the transmission mode for RJ-45 ports is 10/100 Mbps ETHERNET, for RJ-11 port are
1M HomePNA. Therefore, if the Link signal is disrupted (e.g., by unplugging the network cable and plugging it back in
again, or by resetting the power), the port will try to reestablish communications with the attached device via
auto-negotiation. If auto-negotiation fails, then communications are set to half duplex by default. Based on this type
of industry-standard connection policy, if you are using a full-duplex device that does not support auto-negotiation,
communications can be easily lost (i.e., reset to the wrong mode) whenever the attached device is reset or
experiences a power fluctuation. The best way to resolve this problem is to upgrade these devices to a version that
support Ethernet and 1M Home PNA.
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