Cisco 7832 Operating instructions

Troubleshooting
•General Troubleshooting Information, page 1
•Startup Problems, page 3
•Phone Reset Problems, page 5
•Phone Cannot Connect to LAN, page 6
•Audio Problems, page 6
•General Telephone Call Problems, page 7
•Report All Phone Issues with the Configuration Utlility, page 8
•Troubleshooting Procedures, page 8
•Additional Troubleshooting Information, page 9
General Troubleshooting Information
The following table provides general troubleshooting information for the Cisco IP Phone.
Table 1: Cisco IP Phone Troubleshooting
ExplanationSummary
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.
The Cisco 7832 conference phone does not have a PC
port.
Note
Connecting a Cisco IP Phone to
another Cisco IP Phone
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.
Prolonged broadcast storms cause IP
phones to reset, or be unable to make
or answer a call
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ExplanationSummary
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.
Caution
Moving a network connection from
the phone to a workstation
By default, the administrator password settings are locked to prevent
users from making changes that could impact their network
connectivity. You must unlock the administrator password settings
before you can configure them.
If the administrator password is not set in common phone
profile, then user can modify the network settings.
Note
Changing the telephone
configuration
The RxType and the TxType 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. See Display Call Statistics Window
for details.
Codec mismatch between the phone
and another device
The RxSize and the TxSize 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. See Display
Call Statistics Window for details.
Sound sample mismatch between the
phone and another device
A loopback condition can occur when the following conditions are
met:
•The SW Port Configuration option 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 (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, reenable the port from the switch.
Loopback condition
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Troubleshooting
General Troubleshooting Information

Startup Problems
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.
Cisco IP Phone Does Not Go Through the Normal Startup Process
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.
•Verify that the network port is functional:
◦Exchange the Ethernet cables with cables that you know are functional.
◦Disconnect a functioning Cisco IP Phone from another port and connect it to this network port to
verify that the port is active.
◦Connect the Cisco IP Phone that does not start up to a different network port that is known to be
good.
◦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.
•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.
•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.
•If the phone still does not start up properly, perform a factory reset of the phone.
•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.
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Troubleshooting
Startup Problems

Phone Displays Error Messages
Problem
Status messages display errors during startup.
Solution
While 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 the “Display Status Messages Window”section for
instructions about accessing status messages and for a list of potential errors, their explanations, and their
solutions.
Phone Cannot Connect Using DNS
Problem
The DNS settings may be incorrect.
Solution
If you use DNS to access the TFTP server or Third-Party Call Control Manager, you must ensure that you
specify a DNS server.
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
Get a new configuration file remotely from the provisioning server using resync.
Cisco 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.
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Troubleshooting
Phone Displays Error Messages

Phone Reset Problems
If users report that their phones are resetting during calls or while the phones are idle on their desk, you should
investigate the cause. If the network connection and Third Party Call Control connection are stable, a Cisco
IP Phone should not reset.
Typically, a phone resets if it has problems in connecting to the Ethernet network or to Third Party Call
Control.
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 a static IP address, verify that you have entered the correct settings.
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Troubleshooting
Phone Reset Problems

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 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.
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.
Audio Problems
The following sections describe how to resolve audio problems.
No Speech Path
Problem
One or more people on a call do not hear any audio.
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Troubleshooting
Phone Resets During Heavy Network Usage

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.
Choppy Speech
Problem
A user complains of choppy speech on a call.
Cause
There may be a mismatch in the jitter configuration.
Solution
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.
General Telephone Call Problems
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. The phones display the message Configuring IP or Registering.
Solution
1Verify the following:
aThe Ethernet cable is attached.
bThe Third-Party Call Control system is active.
2Audio 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.
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Troubleshooting
Choppy Speech

Cause
Pressing the keys too quickly can result in missed or delayed digits.
Solution
Keys should not be pressed rapidly.
Report All Phone Issues with the Configuration Utlility
If you are working with Cisco TAC to troubleshoot a problem, they typically require the logs from the Problem
Reporting Tool to help resolve the issue. You can generate PRT logs using the Configuration Utlility and
upload them to a remote log server.
Procedure
Step 1 On the Configuration Utility page, select Admin Login >advanced >Info >Debug Info.
Step 2 In the Problem Reports section, click Generate PRT.
The Report Problem dialog appears.
Step 3 Enter the following information in the Report Problem dialog:
a) Enter the date that you experienced the problem in the Date field. The current date appears in this field
by default.
b) Enter the time that you experienced the problem in the Time field. The current time appears in this field
by default.
c) In the Select Problem drop-down list box, choose the description of the problem from the available options.
Step 4 Click Submit in the Report Problem dialog.
The Submit button is enabled only if you select a value in the Select Problem drop-down list box.
You get a notification alert on the Configuration Utility page that indicates if the PRT upload was successful
or not.
Troubleshooting Procedures
These procedures can be used to identify and correct problems.
Check DHCP Settings
Procedure
Step 1 On the phone, press Settings.
Step 2 Check the DHCP server field.
Check the DHCP option for enabled or disabled.
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Troubleshooting
Report All Phone Issues with the Configuration Utlility

Step 3 Check the IP Address, Subnet Mask, and Default Router fields.
If you assign a static IP address to the phone, you must manually enter settings for these options.
Step 4 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:
https://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a00800f0804.shtml
Verify DNS Settings
Procedure
Step 1 On the phone, press Settings.
Step 2 Check that the DNS Server 1 field is set correctly.
Step 3 You should also verify that a CNAME entry was made in the DNS server for the TFTP server and for the
Third-Party Call Control.
You must also ensure that DNS is configured to do reverse lookups.
Additional Troubleshooting Information
If you have additional questions about troubleshooting your phone, go to the following Cisco website and
navigate to the desired phone model:
https://www.cisco.com/cisco/web/psa/troubleshoot.html
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Troubleshooting
Verify DNS Settings

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Troubleshooting
Additional Troubleshooting Information