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Cisco VG248 Analog Phone Gateway Software Configuration Guide
OL-1209-02
Chapter 6 Troubleshooting the VG248
Troubleshooting Hardware Errors
Identifying Power Supply Faults
The internal DC supply voltages are measured continuously (+1.8v, +3.3v, +5.0v,
+12.0v, -48v, -96v).
The 1.8v and 3.3v voltages must be /- 6% of nominal, and the others must
be /- 10%. If any of these values are outside this range, then the VG248
reports a power supply fault.
If the phone power supplies (-48v and -96v) fail, it might indicate that the VG248
is overloaded. Verify that you have not exceeded the maximum ringer
equivalency number (REN) load for each line. You should only have a maximum
of three (3) phones per line.
If one of the other power supplies fails, you should contact a Cisco technical
representative for assistance.
Monitoring Internal Operating Temperature
The VG248 monitors its internal temperature to ensure that it is operating within
the specified limits (the ambient operating environment should be 0° to 40° C or
32° to 104° F). If the VG248 identifies internal temperatures too low or too high,
it generates warning messages. Continuing to operate at ranges exceeding these
limits (either too low or too high) can damage the VG248.
If the operating temperature of the VG248 is too low, there is a risk of
condensation forming inside the device. You should move the device to a warmer
location to prevent this.
If the operating temperature of the VG248 is too high, you should move the device
to a cooler location with improved ventilation. The internal fans on the VG248
maintain the internal temperature consistent with the ambient environment.
Therefore, if the device is in a location that is too warm, its internal temperature
is more likely to exceed the limits. There are two levels of high temperature alert:
•
yellow alert—generates and logs an error, but enables the device to continue
functioning
•
red alert—causes all the phones to be immediately shut down, causing calls
to drop and preventing calls from being made. You must manually restart the
VG248 either by selecting Configure > Restart or by disconnecting power
to the device.
