Performing A Factory Reset; Monitoring The Voice Quality Of Calls - Cisco 6921 Administration Manual

Chapter 9 Troubleshooting and Maintenance

Performing a Factory Reset

When you perform a factory reset of the Cisco Unified IP Phone, the following information is erased or
reset to its default value:
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Before you perform a factory reset, ensure that the following conditions are met:
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To perform a factory reset of a phone, perform the following steps:
Procedure
Unplug the power cable from the phone and then plug it back in.
Step 1
The phone begins its power-up cycle.
While the phone is powering up, and before the Speaker button flashes on and off,
Step 2
press and hold #.
Continue to hold # until each line button flashes on and off in sequence in amber.
Step 3 Release # and press 123456789*0#.
You can press a key twice in a row, but if you press the keys out of sequence, the factory reset will not
take place.
After you press these keys, the line buttons on the phone flash red, and the phone goes through the
factory reset process.
Do not power down the phone until it completes the factory reset process, and the main screen appears.

Monitoring the Voice Quality of Calls

To measure the voice quality of calls that are sent and received within the network, Cisco Unified IP
Phones use these statistical metrics that are based on concealment events. The DSP plays concealment
frames to mask frame loss in the voice packet stream.
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Cisco Unified IP Phone 6921, 6941, and 6961 Administration Guide for Cisco Unified Communications Manager 7.1 (SCCP)
OL-19025-01
User configuration settings—Reset to default values
Network configuration settings—Reset to default values
Call histories—Erased
Locale information—Reset to default values
Phone application—Erased (phone recovers by using the image in the inactive partition of flash to
boot up).
The phone must be on a DHCP-enabled network.
A valid TFTP server must be set in DHCP option 150 or option 66 on the DHCP server.
Concealment Ratio metrics—Show the ratio of concealment frames over total speech frames. An
interval conceal ratio is calculated every 3 seconds.
Concealed Second metrics—Show the number of seconds in which the DSP plays concealment
frames due to lost frames. A severely "concealed second" is a second in which the DSP plays more
than five percent concealment frames.
Monitoring the Voice Quality of Calls
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