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Troubleshoot your phone (for admin)
Feedback?The following table provides general troubleshooting information for the Cisco IP Phone.
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Summary |
Explanation |
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Connecting a Cisco IP Phone to another Cisco IP Phone |
Cisco does not support connecting an IP phone to another IP Phone through the PC port. Each IP Phone should connect directly to a switch port. If phones are connected together in a line by using the PC port, the phones do not work. |
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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. |
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Moving a network connection from the phone to a workstation |
If you power your phone through the network connection, you must be careful if you decide to unplug the network connection of the phone and plug the cable into a desktop computer. 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. |
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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. |
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Codec mismatch between the phone and another device |
The Receiver Codec and the Sender Codec statistics show the codec that is used for a conversation between this Cisco 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. |
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Sound sample mismatch between the phone and another device |
The Receiver Size and the Sender Size statistics show the size of the voice packets that are used in a conversation between this Cisco IP Phone and the other device. The values of these statistics should match. |
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Loopback condition |
A loopback condition can occur when the following conditions are met:
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, reenable the port from the switch. |
After you install a phone into your network and add it to Cisco Unified Communications Manager, the phone should start up as described in the related topic below.
If the phone does not start up properly, see the following sections for troubleshooting information.
Problem
When you connect a Cisco IP Phone to the network port, the phone does not go through the normal startup process as described in the related topic and the phone screen does not 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
To determine whether the phone is functional, use the following suggestions to eliminate other potential problems.
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Verify that the network port is functional:
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Exchange the Ethernet cables with cables that you know are functional.
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Disconnect a functioning Cisco IP Phone from another port and connect it to this network port to verify that the port is active.
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Connect the Cisco IP Phone that does not start up to a different network port that is known to be good.
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Connect the Cisco IP Phone that does not start up directly to the port on the switch, eliminating the patch panel connection in the office.
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Verify that the phone is receiving power:
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If you are using external power, verify that the electrical outlet is functional.
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If you are using in-line power, use the external power supply instead.
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If you are using the external power supply, switch with a unit that you know to be functional.
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If the phone still does not start up properly, perform a factory reset of the phone.
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After you attempt these solutions, if the phone screen on the Cisco IP Phone does not display any characters after at least five minutes, contact a Cisco technical support representative for additional assistance.
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 that displays on the phone screen, the phone is not starting up properly. The phone cannot successfully start up unless it connects to the Ethernet network and it registers with a Cisco Unified Communications Manager server.
In addition, problems with security may prevent the phone from starting up properly. See Troubleshooting procedures for more information.
This article provides the following solutions to troubleshoot the phone connectivity problems:
Phone cannot connect to TFTP server or to Unified CM
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.
Phone cannot connect to TFTP server
Problem
The TFTP server settings may not be correct.
Solution
Check the TFTP settings.
For more information, see Check TFTP settings.
Phone cannot connect to server
Problem
The IP addressing and routing fields may not be configured correctly.
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.
For more information, see Check DHCP settings.
Phone cannot connect using DNS
Problem
The DNS settings may be incorrect.
Solution
If you use DNS to access the TFTP server or Cisco Unified Communications Manager, you must ensure that you specify a DNS server.
For more information, see Check DNS settings.
Phone cannot connect to LAN
Problem
The physical connection to the LAN may be broken.
Solution
Verify that the Ethernet connection to which the Cisco 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.
Problem
If the Cisco Unified Communications Manager (Unified CM) or TFTP services are not running, phones may not be able to start up properly. In this 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 Unified CM 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.
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.
Problem
The phone is not registered with the Cisco Unified Communications Manager
Solution
A Cisco IP Phone can register with a Cisco Unified Communications Manager server only if the phone is added to the server or if autoregistration is enabled. Review the information and procedures in xxx to ensure that the phone is added to the Cisco Unified Communications Manager database.
To verify that the phone is in the Cisco Unified Communications Manager database, choose from Cisco Unified Communications Manager Administration. Click Find to search for the phone based on the MAC Address.
If the phone is already in the Cisco Unified Communications Manager database, the configuration file may be damaged. See Configuration file corruption for assistance.
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.
Problem
The phone screen displays the prompt "Enter your activation code".
Solution
The phone is missing a TFTP address. Check that option 150 is provided by the DHCP server or an alternate TFTP is manually configured.
If users report that their phones are resetting during calls or while the phones are idle, you should investigate the cause. If the network connection and Cisco Unified Communications Manager connection are stable, a phone should not reset.
Typically, a phone resets if it has problems in connecting to the network or to Cisco Unified Communications Manager.
This article provides the following solutions to troubleshoot the phone reset problems:
Phone resets due to 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.
Phone resets due to DHCP setting errors
Problem
The DHCP settings may be incorrect.
Solution
Verify that you have properly configured the phone to use DHCP. Verify that the DHCP server is set up properly. Verify the DHCP lease duration. We recommend that you set the lease duration to 8 days.
Phone resets due to incorrect static IP address
Problem
The static IP address assigned to the phone may be incorrect.
Solution
If the phone is assigned with a static IP address, verify that you have entered the correct settings.
Phone resets during heavy network usage
Problem
If the phone appears to reset during heavy network usage, 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.
Phone resets due to intentional 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 if a Cisco IP Phone received a command from Cisco Unified Communications Manager to reset by pressing .
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If the Restart Cause field displays
Reset-Reset, the phone receives a Reset/Reset from Cisco Unified Communications Manager Administration. -
If the Restart Cause field displays
Reset-Restart, the phone closed because it received a Reset/Restart from Cisco Unified Communications Manager Administration.
Phone resets due to DNS or other connectivity issues
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 by following the procedure in Determine DNS or connectivity issues.
Phone does not power up
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.
The following sections provide troubleshooting information for the security features on the Cisco 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.
This article provides the following solutions to troubleshoot the phone security problems:
- Authentication error, phone cannot authenticate CTL file
- Phone cannot authenticate CTL file
- CTL file authenticates but other configuration files do not authenticate
- ITL file authenticates but other configuration files do not authenticate
- TFTP authorization fails
- Phone does not register
- Signed configuration files are not requested
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.
TFTP authorization fails
Problem
Phone reports TFTP authorization failure.
Cause
The TFTP address for the phone does not exist in the CTL file.
If you created a new CTL file with a new TFTP record, the existing CTL file on the phone may not contain a record for the new TFTP server.
Solution
Check the configuration of the TFTP address in the phone CTL file.
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.
This article provides the following solutions to troubleshoot the video call problems:
No video between two video phones
Problem
Video isn't streaming between two Cisco IP video phones.
Solution
Check to make sure no Media Termination Point (MTP) is being used in the call flow.
Video stutters or drops frames
Problem
When the user is on a video call, the video buffers or drops frames.
Cause
The quality of the image depends upon the bandwidth of the call. Raising the bit rate increases the quality of your video, but requires extra network resources. Always use the bit rate best suited for your type of video. A video call that is 720p and 15 frames per second requires a bit rate of 790 kbps or higher. A video call that is 720p and 30 frames per second requires a bit rate of 1360 kbps or higher.
For additional information about bandwidth, see the Video Transmit Resolution Setup section in Phone Features and Setup.
Solution
Confirm that the Maximum Session Bit Rate for Video Calls parameter is configured to be at least the minimum video bit rate range. On the Cisco Unified Communications Manager, navigate to .
No video during a conference call
Problem
A video call goes to an audio call when I add two or more people to the call.
Solution
The user must use a video conference bridge for ad hoc and meet-me video conferencing.
The following sections help troubleshoot general telephone call problems.
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. The phone screen shows the message
Unregistered.
Solution
- Verify the following:
- The Ethernet cable is attached.
- The Cisco CallManager service is running on the Cisco Unified Communications Manager server.
- Both phones are registered to the same Cisco Unified Communications Manager.
- Audio server debug and capture logs are enabled for both phones. If needed, enable Java debug.
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.
These procedures can be used to identify and correct problems.
You generate a console log when your phone will not connect to the network and you cannot access the Problem Report Tool (PRT).
Before you begin
Connect a console cable to the Auxiliary port on the back of your phone.
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On your phone, press Settings |
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If prompted, enter the password to access the Settings menu. You can get the password from your administrator. |
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Scroll down to the Audio section and tap Aux port. |
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Select Collect console log to collect device logs. |
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Press Settings |
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If prompted, enter the password to access the Settings menu. You can get the password from your administrator. |
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Scroll down to the Network and service section and tap , where <n> represents the type of the TFTP server.
TFTP server 1 is the primary server, TFTP server
2 is the secondary server.
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You can also enable the phone to use an alternate TFTP server. Such a setting is particularly useful if the phone recently moved from one location to another. If the local DHCP does not offer the correct TFTP address, enable the phone to use an
alternate TFTP server.
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Reset phone settings to their default values.
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Modify DHCP and IP settings: |
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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. |
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From Cisco Unified Communications Manager, choose and verify that reference to the server is made by the IP address and not by the DNS name. |
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From Cisco Unified Communications Manager, choose . Click Find to search for this phone. Verify that you have assigned the correct MAC address to this Cisco IP Phone. |
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Power cycle the phone. |
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Press Settings |
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If prompted, enter the password to access the Settings menu. You can get the password from your administrator. |
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Scroll down to the Network and service section and tap , and look at the following options:
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If you are using DHCP, check the IP addresses that your DHCP server distributes. 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/technologies_tech_note09186a00800f0804.shtml |
When you remove a phone from the Cisco Unified Communications Manager database, the configuration file is deleted from the Cisco Unified Communications Manager TFTP server. The phone 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 these DNs from the Cisco Unified Communications Manager database. You can use the Route Plan Report to view and delete unassigned reference numbers. For more information, see the documentation for your particular Cisco Unified Communications Manager release.
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 the phone has no button on the phone with which calls can be answered. These directory numbers should be removed from the phone and deleted if necessary.
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From Cisco Unified Communications Manager, choose and click Find to locate the phone that is experiencing problems. |
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Choose Delete to remove the phone from the Cisco Unified Communications Manager database. When you remove a phone from the Cisco Unified Communications Manager database, the configuration file is deleted from the Cisco Unified Communications Manager TFTP server. The phone 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 these DNs from the Cisco Unified Communications Manager database. You can use the Route Plan Report to view and delete unassigned reference numbers. |
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Add the phone back to the Cisco Unified Communications Manager database. |
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Power cycle the phone. |
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Press Settings |
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If prompted, enter the password to access the Settings menu. You can get the password from your administrator. |
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Scroll down to the Network and service section and tap , where <n> represents the type of the DNS server. 1 is the primary server, 2 and 3 are optional backup DNS servers. For the DNS server with an IPv6 address, check the IPv6 DNS address
1 and IPv6 DNS address 2.
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Verify that a CNAME entry was made in the DNS server for the TFTP server and for the Cisco Unified Communications Manager system. |
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Ensure that DNS is configured to do reverse lookups. |
A service must be activated before it can be started or stopped.
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From Cisco Unified Communications Manager Administration, choose Cisco Unified Serviceability from the Navigation drop-down list and click Go. |
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Choose . |
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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. |
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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. |
If you are experiencing phone problems that you cannot resolve, Cisco TAC can assist you. You will need to turn debugging on for the phone, reproduce the problem, turn debugging off, and send the logs to TAC for analysis.
Because debugging captures detailed information, the communication traffic can slow down the phone, making it less responsive. After you capture the logs, you should turn debugging off to ensure phone operation.
The debug information may include a single digit code that reflects the severity of the situation. Situations are graded as follows:
- 0 - Emergency
- 1 - Alert
- 2 - Critical
- 3 - Error
- 4 - Warn
- 5 - Notification
- 6 - Information
- 7 - Debugging
Contact Cisco TAC for more information and assistance.
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In the Cisco Unified Communications Manager Administration, select one of the following windows: |
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Set the following parameters:
When the Log Server cannot be reached, the phone stops sending debug messages.
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