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Cisco Unified IP Phone 7941G, 7941G-GE, 7942G, 7961G, 7961G-GE, and 7962G Administration Guide for Cisco Unified Communications Manager 9.0 (SCCP and SIP)

Bias-Free Language

The documentation set for this product strives to use bias-free language. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Learn more about how Cisco is using Inclusive Language.

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Book Title

Cisco Unified IP Phone 7941G, 7941G-GE, 7942G, 7961G, 7961G-GE, and 7962G Administration Guide for Cisco Unified Communications Manager 9.0 (SCCP and SIP)

Chapter Title

Troubleshooting and Maintenance

Results

Updated:
June 29, 2020

Chapter: Troubleshooting and Maintenance

Troubleshooting and Maintenance

Troubleshooting and Maintenance Overview

This chapter provides information that can assist you in troubleshooting problems with your Cisco Unified IP Phone or with your IP telephony network. It also explains how to clean and maintain your phone.

For additional troubleshooting information, see the Using the 79xx Status Information For Troubleshooting tech note. That document is available to registered Cisco.com users at this URL:

http:/​/​www.cisco.com/​en/​US/​products/​hw/​phones/​ps379/​products_​tech_​note09186a00800945bd.shtml

Troubleshooting

This section contains the following topics.

Startup Problems

After installing a Cisco Unified IP Phone into your network and adding it to Cisco Unified Communications Manager, the phone should start up as described in the Phone Startup Process Verification. If the phone does not start up properly, see the following sections for troubleshooting information.

Cisco Unified IP Phone Does Not Go Through Normal Startup Process

Problem

When you connect a Cisco Unified IP Phone into the network port, the phone should go through its normal startup process and the LCD screen should display information.

Cause

If the phone does not go through the startup process, the cause may be faulty cables, bad connections, network outages, lack of power, or the phone may not be functional.

Solution

The following suggestions can help determine if the phone is functional:

  1. Verify that the network port is functional:

    • Exchange the Ethernet cables with cables that you know are functional.

    • Disconnect a functioning Cisco Unified IP Phone from another port and connect it to this network port to verify the port is active.

    • Connect the Cisco Unified IP Phone that will not start up to a different network port that is known to be good.

    • Connect the Cisco Unified IP Phone that will not start up directly to the port on the switch, eliminating the patch panel connection in the office.

  2. Verify that the phone is receiving power:

    • If you are using external power, verify that the electrical outlet is functional.

    • If you are using in-line power, use the external power supply instead.

    • If you are using the external power supply, switch with a unit that you know to be functional.

  3. If the phone still does not start up properly, power up the phone with the handset off-hook. When the phone is powered up in this way, it attempts to launch a backup software image.

  4. If the phone still does not start up properly, perform a factory reset of the phone. For instructions, see Perform Factory Reset.

If after attempting these solutions, the LCD screen on the Cisco Unified IP Phone does not display any characters after at least five minutes, contact a Cisco technical support representative for additional assistance.

Cisco Unified IP Phone Does not Register with Cisco Unified Communications Manager

If the phone proceeds past the first stage of the startup process (LED buttons flashing on and off) but continues to cycle through the messages displaying on the LCD screen, the phone is not starting up properly. The phone cannot successfully start up unless it is connected to the Ethernet network and it has registered with a Cisco Unified Communications Manager server.

In addition, problems with security may prevent the phone from starting up properly. See Cisco Unified IP Phone Security Problems for more information.

Phone Displays Error Messages
Problem

Status messages display errors during startup.

Solution

As the phone cycles through the startup process, you can access status messages that might provide you with information about the cause of a problem. See Status Messages Screen for instructions about accessing status messages and for a list of potential errors, their explanations, and their solutions.

Phone Cannot Connect to TFTP Server or to Cisco Unified Communications Manager
Problem

If the network is down between the phone and either the TFTP server or Cisco Unified Communications Manager, the phone cannot start up properly.

Solution

Ensure that the network is currently running.

TFTP Server Settings
Problem

The TFTP server settings may not be correct.

Solution

Check the TFTP settings. See Check TFTP Settings.

IP Address and Routing
Problem

The IP addressing and routing fields may not be correctly configured.

Solution

You should verify the IP addressing and routing settings on the phone. If you are using DHCP, the DHCP server should provide these values. If you have assigned a static IP address to the phone, you must enter these values manually. See Check DHCP Settings.

DNS Settings
Problem

The DNS settings may be incorrect.

Solution

If you are using DNS to see the TFTP server or to Cisco Unified Communications Manager, you must ensure that you have specified a DNS server. See Verify DNS Settings.

Cisco Unified Communications Manager Settings On Phone
Problem

The phone may have the correct Cisco Unified Communications Manager information.

Solution

On the Cisco Unified IP Phone, press the Settings button, choose Device Configuration, and look at the Unified CM Configuration options. The Cisco Unified IP Phone attempts to open a TCP connection to all the Cisco Unified Communications Manager servers that are part of the assigned Cisco Unified Communications Manager group. If none of these options contain IP addresses or show Active or Standby, the phone is not properly registered with Cisco Unified Communications Manager. See Phone Cannot Connect to TFTP Server or to Cisco Unified Communications Manager for tips on resolving this problem.

Cisco CallManager and TFTP Services Are Not Running
Problem

If the Cisco CallManager or TFTP services are not running, phones may not be able to start up properly. In such a situation, it is likely that you are experiencing a systemwide failure, and other phones and devices are unable to start up properly.

Solution

If the Cisco CallManager service is not running, all devices on the network that rely on it to make phone calls are affected. If the TFTP service is not running, many devices cannot start up successfully. For more information, see Start Service.

Configuration File Corruption
Problem

If you continue to have problems with a particular phone that other suggestions in this chapter do not resolve, the configuration file may be corrupted.

Solution

Create a new phone configuration file. See Create New Phone Configuration File.

Cisco Unified Communications Manager Phone Registration
Problem

The phone is not registered with the Cisco Unified Communications Manager

Solution

A Cisco Unified IP Phone can register with a Cisco Unified Communications Manager server only if the phone has been added to the server or if auto-registration is enabled. Review the information and procedures in Cisco Unified Communications Manager Phone Addition Methods to ensure that the phone has been added to the Cisco Unified Communications Manager database.

To verify that the phone is in the Cisco Unified Communications Manager database, choose Device > Phone > Find from Cisco Unified Communications Manager Administration to search for the phone based on its MAC Address. For information about determining a MAC address, see Cisco Unified IP Phone MAC Address Determination.

If the phone is already in the Cisco Unified Communications Manager database, its configuration file may be damaged. See Configuration File Corruption for assistance.

Cisco Unified IP Phone Cannot Obtain IP Address

Problem

If a phone cannot obtain an IP address when it starts up, the phone may not be on the same network or VLAN as the DHCP server, or the switch port to which the phone connects may be disabled.

Solution

Ensure that the network or VLAN to which the phone connects has access to the DHCP server, and ensure that the switch port is enabled.

Cisco Unified IP Phone Displays Security Error Message

Problem

The phone displays Security Error on the screen.

Cause

When a Cisco Unified IP Phone boots, it performs an internal Power On Self Test (POST). POST checks for existing encryption functionality. If POST detects that encryption functionality is missing, the phone fails to boot, and the message "Security Error" appears on the screen.

Solution

To correct the problem, perform the following steps:

  1. Reset the phone manually.

  2. If the phone does not start up properly, power up the phone with the handset off-hook. When the phone is powered up in this way, it attempts to launch a backup software image.

  3. If the phone still does not start up properly, perform a factory reset of the phone. For instructions, see Perform Factory Reset.

Cisco Unified IP Phone Resets Unexpectedly

If users report that their phones are resetting during calls or while idle on their desk, you should investigate the cause. If the network connection and Cisco Unified Communications Manager connection are stable, a Cisco Unified IP Phone should not reset on its own.

A phone resets if it has problems connecting to the Ethernet network or to Cisco Unified Communications Manager.

Physical Connection Problems

Problem

The physical connection to the LAN may be broken.

Solution

Verify that the Ethernet connection to which the Cisco Unified IP Phone connects is up. For example, check whether the particular port or switch to which the phone connects is down and that the switch is not rebooting. Also ensure that no cable breaks exist.

Intermittent Network Outages

Problem

Your network may be experiencing intermittent outages.

Solution

Intermittent network outages affect data and voice traffic differently. Your network might be experiencing intermittent outages without detection. If so, data traffic can resend lost packets and verify that packets are received and transmitted. However, voice traffic cannot recapture lost packets. Rather than retransmitting a lost network connection, the phone resets and attempts to reconnect to the network. Contact the system administrator for information on known problems in the voice network.

DHCP Setting Errors

Problem

The DHCP settings may be incorrect.

Solution

The following suggestions can help you determine if the phone has been properly configured to use DHCP:

  1. Verify that you have properly configured the phone to use DHCP. See Network Configuration Menu for more information.

  2. Verify that the DHCP server has been set up properly.

  3. Verify the DHCP lease duration. We recommend that you set the lease duration to 8 days.

Cisco Unified IP Phones send messages with request type 151 to renew their DHCP address leases. If the DHCP server expects messages with request type 150, the lease renewal is denied, forcing the phone to restart and request a new IP address from the DHCP server.

Static IP Address Setting Errors

Problem

The static IP address assigned to the phone may be incorrect.

Solution

If the phone has been assigned a static IP address, verify that you have entered the correct settings.

Voice VLAN Setup Errors

Problem

If the Cisco Unified IP Phone appears to reset during heavy network usage (for example, following extensive web surfing on a computer connected to same switch as phone), it is likely that you do not have a voice VLAN configured.

Solution

Isolating the phones on a separate auxiliary VLAN increases the quality of the voice traffic.

Phones Have Not Been Intentionally Reset

Problem

If you are not the only administrator with access to Cisco Unified Communications Manager, you should verify that no one else has intentionally reset the phones.

Solution

You can check whether a Cisco Unified IP Phone received a command from Cisco Unified Communications Manager to reset by pressing the Applications Menu button on the phone and choosing Settings > Status > Network Statistics. If the phone was recently reset one of these messages appears:

  • Reset-Reset: Phone received a Reset-Reset request from Cisco Unified Communications Manager Administration.

  • Reset-Restart: Phone received a Reset-Restart request from Cisco Unified Communications Manager Administration.

DNS or Other Connectivity Errors

Problem

The phone reset continues and you suspect DNS or other connectivity issues.

Solution

If the phone continues to reset, eliminate DNS or other connectivity errors with Determine DNS or Connectivity Issues.

Power Connection Problems

Problem

The phone does not appear to be powered up.

Solution

In most cases, a phone restarts if it powers up by using external power but loses that connection and switches to PoE. Similarly, a phone may restart if it powers up by using PoE and then connects to an external power supply.

Cisco Unified IP Phone Security Problems

The following sections provide troubleshooting information for the security features on the Cisco Unified IP Phone. For information about the solutions for any of these issues, and for additional troubleshooting information about security, see Cisco Unified Communications Manager Security Guide.

CTL File Problems

The following sections describe problems with the CTL file:

Authentication Error, Phone Cannot Authenticate CTL File
Problem

A device authentication error occurs.

Cause

CTL file does not have a Cisco Unified Communications Manager certificate or has an incorrect certificate.

Solution

Install a correct certificate.

Phone Cannot Authenticate CTL File
Problem

Phone cannot authenticate the CTL file.

Cause

The security token that signed the updated CTL file does not exist in the CTL file on the phone.

Solution

Change the security token in the CTL file and install the new file on the phone.

CTL File Authenticates but Other Configuration Files Do Not Authenticate
Problem

Phone cannot authenticate any configuration files other than the CTL file.

Cause

A bad TFTP record exists, or the configuration file may not be signed by the corresponding certificate in the phone Trust List.

Solution

Check the TFTP record and the certificate in the Trust List.

ITL File Authenticates but Other Configuration Files Do Not Authenticate
Problem

Phone cannot authenticate any configuration files other than the ITL file.

Cause

The configuration file may not be signed by the corresponding certificate in the phone Trust List.

Solution

Re-sign the configuration file by using the correct certificate.

Phone Does Not Register
Problem

Phone does not register with Cisco Unified Communications Manager.

Cause

The CTL file does not contain the correct information for the Cisco Unified Communications Manager server.

Solution

Change the Cisco Unified Communications Manager server information in the CTL file.

Signed Configuration Files Are Not Requested
Problem

Phone does not request signed configuration files.

Cause

The CTL file does not contain any TFTP entries with certificates.

Solution

Configure TFTP entries with certificates in the CTL file.

802.1X Authentication Problems

802.1X authentication problems can be broken down into the categories described in the following table:

If all the following conditions apply,

See
  • Phone cannot obtain a DHCP-assigned IP address
  • Phone does not register with Cisco Unified Communications Manager
  • Phone status display as Configuring IP or Registering
  • 802.1X Authentication Status displays as Held (see 802.1X Authentication and Status).
  • Status menu displays 802.1x status as Failed (see Call Statistics Screen).

802.1X enabled on phone but phone does not authenticate

  • Phone cannot obtain a DHCP-assigned IP address
  • Phone does not register with Cisco Unified Communications Manager
  • Phone status display as Configuring IP or Registering
  • 802.1X Authentication Status displays as Disabled (see 802.1X Authentication and Status).
  • Status menu displays DHCP status as timing out (see Call Statistics Screen).

802.1X not enabled

  • Phone cannot obtain a DHCP-assigned IP address
  • Phone does not register with Cisco Unified Communications Manager
  • Phone status display as Configuring IP or Registering
  • Cannot access phone menus to verify 802.1X status

Factory reset of phone has deleted 802.1X shared secret

802.1X Enabled on Phone but Phone Does Not Authenticate
Problem

The phone cannot authenticate.

Cause

These errors typically indicate that 802.1X is enabled on the phone, but the phone is unable to authenticate.

Solution

  1. Verify that you have properly configured the required components. See 802.1X Authentication for more information

  2. Confirm that the shared secret is configured on the phone. See Security Configuration Menu for more information.

    • If the shared secret is configured, verify that you have the same shared secret entered on the authentication server.

    • If the shared secret is not configured, enter it, and ensure that it matches the shared secret on the authentication server.

802.1X Not Enabled
Problem

The phone does not have 802.1X configured.

Cause

These errors typically indicate that 802.1X is not enabled on the phone.

Solution

To enable it, see Security Configuration Menu for information on enabling 802.1X on the phone.

Factory Reset of Phone has Deleted 802.1X Shared Secret
Problem

After a reset, the phone does not authenticate.

Cause

These errors typically indicate that the phone has completed a factory reset while 802.1X was enabled. A factory reset deletes the shared secret, which is required for 802.1X authentication and network access.

Solution

To resolve this, you have two options:

  • Temporarily disable 802.1X on the switch.

  • Temporarily move the phone to a network environment that is not using 802.1X authentication.

After the phone starts up normally in one of these conditions, you can access the 802.1X configuration menus and re-enter the shared secret.

Audio and Video Problems

The following sections describe how to resolve audio and video problems.

Phone Display Is Wavy

Problem

The display appears to have rolling lines or a wavy pattern.

Cause

The phone might be interacting with certain types of older fluorescent lights in the building.

Solution

Move the phone away from the lights or replace the lights to resolve the problem.

No Speech Path

Problem

One or more people on a call do not hear any audio.

Solution

When at least one person in a call does not receive audio, IP connectivity between phones is not established. Check the configuration of routers and switches to ensure that IP connectivity is properly configured.

General Telephone Call Problems

The following sections help troubleshoot general telephone call problems.

VPN-Connected Phone Does Not Log Calls

Problem

A remote location (home office) phone that is connected through the VPN does not log missed, placed, or received calls.

Cause

Without explicitly setting the Alternate TFTP setting, the Cisco IP Phone cannot contact the TFTP server and download the configuration and other files, and function properly.

Solution

Set up the phone to use the Alternate TFTP server and configure the TFTP server IP address.

Related Tasks
Set Up Remote Phone

Phone Does Not Recognize DTMF Digits or Digits Are Delayed

Problem

The user complains that numbers are missed or delayed when the keypad is used.

Cause

Pressing the keys too quickly can result in missed or delayed digits.

Solution

Keys should not be pressed rapidly.

Phone Call Cannot Be Established

Problem

A user complains about not being able to make a call.

Cause

The phone does not have a DHCP IP address, is unable to register to Cisco Unified Communications Manager. Phones with an LCD display show the message Configuring IP or Registering. Phones without an LCD display play the reorder tone (instead of dial tone) in the handset when the user attempts to make a call.

Solution

  1. Verify the following:

    1. The Ethernet cable is attached.
    2. The Cisco CallManager service is running on the Cisco Unified Communications Manager server.
    3. Both phones are registered to the same Cisco Unified Communications Manager.

  2. Audio server debug and capture logs are enabled for both phones. If needed, enable Java debug.

Troubleshooting Procedures

These procedures can be used to identify and correct problems.

Set Up Remote Phone

Cisco IP Phones that are configured for SSL VPN to ASA using the built-in client in a remote location (for example, a home office) have a special configuration requirement.

We recommend that you provide the phone with an Alternate TFTP server setting manually. This setting allows the phone to download the configuration and other files from TFTP. The phone in a remote location (home office) cannot correctly provide OPTION 150 to the phone using DHCP.

The IP phone can register to the last-known Cisco Unified Communications Manager, but any configuration updates cannot applied until you configure the manual TFTP server address.

Procedure
    Step 1   On the phone, select Applications.
    Step 2   Navigate to the IPv4 Settings window.
    Step 3   Scroll to the Alternate TFTP option and set the field to Yes.
    Step 4   In the TFTP Server 1 field, set the TFTP server address.
    Step 5   Save the changes.

    Check TFTP Settings

    Procedure
      Step 1   You can determine the IP address of the TFTP server used by the phone by pressing Settings, choosing Network Configuration > IPv4 and scrolling to the TFTP Server 1 option.
      Step 2   If you have assigned a static IP address to the phone, you must manually enter a setting for the TFTP Server 1 option. See Network Configuration Menu.
      Step 3   If you are using DHCP, the phone obtains the address for the TFTP server from the DHCP server. Check the IP address configured in Option 150.
      Step 4   You can also enable the phone to use an alternate TFTP server. Such a setting is particularly useful if the phone was recently moved from one location to another. See Network Configuration Menu for instructions.

      Check DHCP Settings

      Procedure
        Step 1   On the Cisco Unified IP Phone, choose Settings > Network Configuration > IPv4 Configuration, and look at the following options:
        Step 2   If you are using DHCP, check the IP addresses distributed by your DHCP server. See the Understanding and Troubleshooting DHCP in Catalyst Switch or Enterprise Networks document, available at this URL: http:/​/​www.cisco.com/​en/​US/​tech/​tk648/​tk361/​tech_​tech_​notes_​list.html

        Verify DNS Settings

        To verify DNS settings, perform these steps.

        Procedure
          Step 1   Verify this setting by pressing Settings.
          Step 2   Choose Network Configuration and scroll to the DNS Server 1 option.
          Step 3   Verify that a CNAME entry exists in the DNS server for the TFTP server and for the Cisco Unified Communications Manager system.
          Step 4   Ensure that DNS is configured to do reverse look-ups.

          Start Service


          Note

          A service must be activated before it can be started or stopped. To activate a service, choose Tools > Service Activation.

          To start a service, follow these steps:

          Procedure
            Step 1   From Cisco Unified Communications Manager Administration, choose Cisco Unified Serviceability from the Navigation drop-down list and click Go.
            Step 2   Choose Tools > Control Center - Feature Services.
            Step 3   Choose the primary Cisco Unified Communications Manager server from the Server drop-down list.

            The window displays the service names for the server that you chose, the status of the services, and a service control panel to start or stop a service.

            Step 4   If a service has stopped, click the corresponding radio button and then click Start.

            The Service Status symbol changes from a square to an arrow.

            Create New Phone Configuration File

            If you continue to have problems with a particular phone that other suggestions in this chapter do not resolve, the configuration file may be corrupted.


            Note
            • When you remove a phone from the Cisco Unified Communications Manager database, its configuration file is deleted from the Cisco Unified Communications Manager TFTP server. The phone’s directory number or numbers remain in the Cisco Unified Communications Manager database. They are called "unassigned DNs" and can be used for other devices. If unassigned DNs are not used by other devices, delete them from the Cisco Unified Communications Manager database. You can use the Route Plan Report to view and delete unassigned reference numbers. See Cisco Unified Communications Manager Administration Guide for more information.
            • Changing the buttons on a phone button template, or assigning a different phone button template to a phone, may result in directory numbers that are no longer accessible from the phone. The directory numbers are still assigned to the phone in the Cisco Unified Communications Manager database, but there is no button on the phone with which calls can be answered. These directory numbers should be removed from the phone and deleted if necessary.

            To create a new configuration file, follow these steps:

            Procedure
              Step 1   From Cisco Unified Communications Manager, choose Device > Phone > Find to locate the phone experiencing problems.
              Step 2   Choose Delete to remove the phone from the Cisco Unified Communications Manager database.
              Step 3   Add the phone back to the Cisco Unified Communications Manager database. See Cisco Unified Communications Manager Phone Addition Methods for details.
              Step 4   Power cycle the phone.

              Determine DNS or Connectivity Issues

              If the phone continues to reset, follow these steps to eliminate DNS or other connectivity errors:

              Procedure
                Step 1   Use Erase to reset phone settings to their default values. See Cisco Unified IP Phone Reset or Restore for details.
                Step 2   Modify DHCP and IP settings:
                1. Disable DHCP. See Network Configuration Menu for instructions.
                2. Assign static IP values to the phone. See Network Configuration Menu for instructions. Use the same default router setting used for other functioning Cisco Unified IP Phones.
                3. Assign a TFTP server. See Network Configuration Menu for instructions. Use the same TFTP server used for other functioning Cisco Unified IP Phones.
                Step 3   On the Cisco Unified Communications Manager server, verify that the local host files have the correct Cisco Unified Communications Manager server name mapped to the correct IP address.
                Step 4   From Cisco Unified Communications Manager, choose System > Server and verify that the server is referred to by its IP address and not by its DNS name.
                Step 5   From Cisco Unified Communications Manager, choose Device > Phone > Find and verify that you have assigned the correct MAC address to this Cisco Unified IP Phone. For information about determining a MAC address, see Cisco Unified IP Phone MAC Address Determination.
                Step 6   Power cycle the phone.

                General Troubleshooting Information

                The following table provides general troubleshooting information for the Cisco Unified IP Phone.

                Table 1 Cisco Unified IP Phone Troubleshooting

                Summary

                Explanation

                Connecting a Cisco Unified IP Phone to another Cisco Unified IP Phone

                Cisco does not support connecting an IP Phone to another IP Phone through the PC port. Each IP Phone should directly connect to a switch port. If phones are connected together in a line using the PC port, the phones will not work.

                Poor quality when calling digital cell phones using the G.729 protocol

                In Cisco Unified Communications Manager, you can configure the network to use the G.729 protocol. The default protocol is G.711. When using G.729, calls between an IP Phone and a digital cellular phone will have poor voice quality. Use G.729 only when absolutely necessary.

                Prolonged broadcast storms cause IP phones to reset, or be unable to make or answer a call

                A prolonged Layer 2 broadcast storm lasting several minutes on the voice VLAN may cause IP Phones to reset, lose an active call, or be unable to initiate or answer a call. Phones may not come up until a broadcast storm ends.

                Moving a network connection from the phone to a workstation

                If you are powering your phone through the network connection, you must be careful if you decide to unplug the phone’s network connection and plug the cable into a desktop computer.

                Caution   

                The network card in the computer cannot receive power through the network connection; if power comes through the connection, the network card can be destroyed. To protect a network card, wait 10 seconds or longer after unplugging the cable from the phone before plugging it into a computer. This delay gives the switch enough time to recognize that there is no longer a phone on the line and to stop providing power to the cable.

                Changing the telephone configuration

                By default, the network configuration options are locked to prevent users from making changes that could impact their network connectivity. You must unlock the network configuration options before you can configure them. See Unlock and Lock Options for details.

                Phone resetting

                The phone resets when it loses contact with the Cisco Unified Communications Manager software. This lost connection can be due to any network connectivity disruption, including cable breaks, switch outages, and switch reboots.

                Codec mismatch between the phone and another device

                The RxType and the TxType statistics show the codec that is being used for a conversation between this Cisco Unified IP phone and the other device. The values of these statistics should match. If they do not, verify that the other device can handle the codec conversation, or that a transcoder is in place to handle the service.

                See Call Statistics Screen for information about displaying these statistics.

                Sound sample mismatch between the phone and another device

                The RxSize and the TxSize statistics show the size of the voice packets that are being used in a conversation between this Cisco Unified IP phone and the other device. The values of these statistics should match.

                See Call Statistics Screen for information about displaying these statistics.

                Gaps in voice calls

                Check the AvgJtr and the MaxJtr statistics. A large variance between these statistics might indicate a problem with jitter on the network or periodic high rates of network activity.

                See Call Statistics Screen for information about displaying these statistics.

                Loopback condition

                A loopback condition can occur when the following conditions are met:

                • The SW Port Configuration option in the Network Configuration menu on the phone is set to 10 Half (10-BaseT / half duplex)
                • The phone receives power from an external power supply
                • The phone is powered down or the power supply is disconnected

                In this case, the switch port on the phone can become disabled and the following message appears in the switch console log:

                HALF_DUX_COLLISION_EXCEED_THRESHOLD

                To resolve this problem, re-enable the port from the switch.

                Peer Firmware Sharing fails.

                If the Peer Firmware Sharing fails, the phone will default to using the TFTP server to download firmware. Access the log messages stored on the remote logging machine to help debug the Peer Firmware Sharing feature.

                Note   

                These log messages are different from the log messages sent to the phone log.

                Cisco VT Advantage/Unified Video Advantage (CVTA)

                If you are having problems getting CVTA to work, make sure that the PC Port is enabled, and that CDP is enabled on the PC port.

                See Network Configuration Menu for more information.

                Phone call cannot be established

                The phone does not have a DHCP IP address, is unable to register to Cisco Unified Communications Manager, and shows a Configuring IP or Registering message.

                Verify the following:

                1. The Ethernet cable is attached.

                2. The Cisco CallManager service is running on the Cisco Unified Communications Manager server.

                3. Both phones are registered to the same Cisco Unified Communications Manager.

                4. Audio server debug and capture logs are enabled for both phones. If needed, enable Java debug.

                Call established with the iLBC protocol does not show that the iLBC codec is being used

                Call statistics display does not show iLBC as the receiver/sender codec.

                1. Check the following by using Cisco Unified Communications Manager Administration:

                  • Both phones are in the iLBC device pool.

                  • The iLBC device pool is configured with the iLBC region.

                  • The iLBC region is configured with the iLBC codec.

                2. Capture a sniffer trace between the phone and Cisco Unified Communications Manager and verify that SCCP messages, OpenReceiveChannel, and StationMediaTransmit messages have media payload type value equal to 86. If so, the problem is with the phone; otherwise, the problem is with the Cisco Unified Communications Manager configuration.

                3. Enable audio server debug and capture logs from both phones. If needed, enable Java debug.

                General Troubleshooting Tips for Cisco Unified IP Phone Expansion Module

                The following table provides general troubleshooting information for the Cisco Unified IP Phone Expansion Module.

                Table 2 Cisco Unified IP Phone Expansion Module Troubleshooting

                Problem

                Solution

                No display on the Cisco Unified IP Phone Expansion Module.

                Verify that all of the cable connections are correct.

                Verify that you have power to the Cisco Unified IP Phone Expansion Module.

                Lighted buttons on the first Cisco Unified IP Phone Expansion Module are all red.

                Verify that the Cisco Unified IP Phone Expansion Module is configured in Cisco Unified Communications Manager.

                Lighted buttons on the second Cisco Unified IP Phone Expansion Module are all amber.

                Verify that the Cisco Unified IP Phone Expansion Module is configured in Cisco Unified Communications Manager.

                Cisco Unified IP Phone Reset or Restore

                There are two general methods for resetting or restoring the Cisco Unified IP Phone.

                Basic Reset

                Performing a basic reset of a Cisco Unified IP Phone provides a way to recover if the phone experiences an error and provides a way to reset or restore various configuration and security settings.

                The following table describes the ways to perform a basic reset. You can reset a phone with any of these operations after the phone has started up. Choose the operation that is appropriate for your situation.

                Table 3 Basic Reset Methods

                Operation

                Performing

                Explanation

                Restart phone

                Press the Services, Settings, or Directories button and then press **#**.

                Resets any user and network configuration changes that you have made, but that the phone has not written to its Flash memory, to previously saved settings, then restarts the phone.

                Erase softkey

                From the Settings menu, unlock phone options (see Unlock and Lock Options). Then press the Erase softkey.

                Resets user and network configuration settings to their default values, deletes the CTL file from the phone, and restarts the phone.

                From the Network Configuration menu, unlock phone options (see Unlock and Lock Options). Then press the Erase softkey.

                Resets network configuration settings to their default values and resets the phone. This method causes DHCP to reconfigure the IP address of the phone.

                From the Security Configuration menu, unlock phone options (see Unlock and Lock Options). Then press the Erase softkey.

                Deletes the CTL file from the phone and restarts the phone.

                Perform 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:

                • CTL file: Erased
                • LSC: Erased
                • 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. The phone recovers by loading the appropriate default load file (term62.default.loads, term61.default.loads, term42.default.loads, or term41.defaults.loads) depending on the phone model.

                Before you perform a factory reset, ensure that the following conditions are met:

                • 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.
                • The default load file for your phone model and the files specified in that file should be available on the TFTP server that is specified by the DHCP packet.

                To perform a factory reset of a phone, perform the following steps:

                Procedure
                  Step 1   Unplug the power cable from the phone and then plug the cable back in.

                  The phone begins its power-up cycle.

                  Step 2   While the phone is powering up, and before the Speaker button flashes on and off, 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.

                  Additional Troubleshooting Information

                  If you have additional questions about troubleshooting the Cisco Unified IP Phones, these Cisco.com websites provide you with more tips.

                  Maintenance

                  This section includes the following topics

                  Quality Report Tool

                  The Quality Report Tool (QRT) is a voice quality and general problem-reporting tool for the Cisco Unified IP Phone. The QRT feature is installed as part of the Cisco Unified Communications Manager installation.

                  You can configure Cisco Unified IP Phones with QRT. When you do so, users can report problems with phone calls pressing QRT. This softkey is available only when the Cisco Unified IP Phone is in the Connected, Connected Conference, Connected Transfer, or OnHook states.

                  When a user presses QRT, a list of problem categories appears. The user selects the appropriate problem category, and this feedback is logged in an XML file. Actual information logged depends on the user selection, and if the destination device is a Cisco Unified IP Phone.

                  For more information about using QRT, see the Cisco Unified Serviceability Administration Guide.

                  Voice Quality Monitoring

                  To measure the voice quality of calls that are sent and received within the network, Cisco Unified IP Phones use the following statistical metrics that are based on concealment events. The DSP plays concealment frames to mask frame loss in the voice packet stream.

                  • Concealment Ratio metrics: Shows the ratio of concealment frames over total speech frames. The phone calculates an interval conceal ratio every 3 seconds.

                  • Concealed Second metrics: Shows 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.

                  • MOS-LQK metrics: Uses a numeric score to estimate the relative voice listening quality. The Cisco Unified IP Phone calculates the mean opinion score (MOS) for listening quality (LQK) based audible concealment events due to frame loss in the preceding 8 seconds, and includes perceptual weighting factors such as codec type and frame size.

                    The phone uses the Cisco proprietary algorithm, Cisco Voice Transmission Quality (CVTQ) index, to produce MOS LQK scores. Depending on the MOS LQK version number, these scores might be compliant with the International Telecommunications Union (ITU) standard P.564. This standard defines evaluation methods and performance accuracy targets that predict listening quality scores based on observation of actual network impairment.


                  Note

                  Concealment ratio and concealment seconds are primary measurements based on frame loss while MOS LQK scores project a "human-weighted" version of the same information on a scale from 5 (excellent) to 1 (bad) for measuring listening quality.

                  Listening quality scores (MOS LQK) relate to the clarity or sound of the received voice signal. Conversational quality scores (MOS CQ, such as G.107) include impairment factors, such as delay, that degrade the natural flow of conversation.

                  You can access voice quality metrics from the Cisco Unified IP Phone by using the Call Statistics screen or remotely by using Streaming Statistics.

                  Related Information
                  Call Statistics Screen
                  Remote Monitoring

                  Voice Quality Metric Interpretation

                  To use the metrics for monitoring voice quality, note the typical scores under normal conditions of zero packet loss and use the metrics as a baseline for comparison.

                  It is important to distinguish significant changes from random changes in metrics. Significant changes are scores that change about 0.2 MOS or greater and persist in calls that last longer than 30 seconds. Conceal Ratio changes should indicate greater than 3 percent frame loss.

                  MOS LQK scores can vary based on the codec that the Cisco Unified IP Phone uses.

                  The following codecs on the Cisco Unified IP Phones 7962G and 7942G provide these maximum MOS LQK scores under normal conditions with zero frame loss:

                  • G.711 gives 4.5

                  • G.722 gives 4.5

                  • G.728/iLBC gives 3.9

                  • G.729 A/AB gives 3.8

                  The following codecs on the Cisco Unified IP Phones 7961G/G-GE and 7941G/G-GE provide these maximum MOS LQK scores under normal conditions with zero frame loss:

                  • G.711 codec gives 4.5 score

                  • G.729A/ AB gives 3.7


                  Note
                  • CVTQ does not support wideband (7 kHz) speech codecs, because ITU has not defined the extension of the technique to wideband. Therefore, MOS scores that correspond to G.711 performance are reported for G.722 calls to allow basic quality monitoring, rather than not reporting an MOS score.

                  • Reporting G.711-scale MOS scores for wideband calls through the use of CVTQ allows basic quality classifications to be indicated as good/normal or bad/abnormal. Calls with high scores (approximately 4.5) indicate high quality/low packet loss, and lower scores (approximately 3.5) indicate low quality/high packet loss.

                  • Unlike MOS, the Conceal Ratio and Concealed Seconds metrics remain valid and useful for both wideband and narrowband calls.

                  A Conceal Ratio of zero indicates that the IP network is delivering frames and packets on time with no loss.

                  Voice Quality Troubleshooting Tips

                  When you observe significant and persistent changes to metrics, use the following table for general troubleshooting information:

                  Table 4 Changes to Voice Quality Metrics

                  Metric change

                  Condition

                  MOS LQK scores decrease significantly

                  Network impairment from packet loss or high jitter:

                  • Average MOS LQK decreases could indicate widespread and uniform impairment.
                  • Individual MOS LQK decreases indicate bursty impairment.

                  Cross-check with Conceal Ratio and Conceal Seconds for evidence of packet loss and jitter.

                  MOS LQK scores decrease significantly

                  Check to see whether the phone is using a different codec than expected (RxType and TxType).

                  Check to see whether the MOS LQK version changed after a firmware upgrade.

                  Conceal Ratio and Conceal Seconds increase significantly

                  • Network impairment from packet loss or high jitter.

                  Conceal Ratio is near or at zero, but the voice quality is poor.

                  Noise or distortion in the audio channel such as echo or audio levels.

                  Tandem calls that undergo multiple encode/decode, such as calls to a cellular network or calling card network.

                  Acoustic problems coming from a speakerphone, handsfree cellular phone, or wireless headset.

                  Check packet transmit (TxCnt) and packet receive (RxCnt) counters to verify that voice packets are flowing.


                  Note

                  Voice quality metrics do not account for noise or distortion, only frame loss.

                  Cisco Unified IP Phone Cleaning

                  To clean your Cisco Unified IP phone, use a soft, dry cloth to wipe the phone screen. Do not apply liquids or powders directly on the phone. As with all non-weather-proof electronics, liquids and powders can damage the components and cause failures.

                  Disable the screen before cleaning it so that you will not inadvertently choose a feature from the pressure of the cleaning cloth. To disable the screen, press Display for more than one second. The phone displays Touchscreen Disabled or Phone Screen Disabled and the Display button flashes green.

                  After one minute, the screen automatically reenables itself. To reenable the screen before that, press the flashing Display button for more than one second. The phone displays Touchscreen Enabled or Phone Screen Enabled.

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