Poor Audio Quality With Calls That Route Outside Cisco Unified Communications Manager; General Telephone Call Problems; Phone Call Cannot Be Established; Phone Does Not Recognize Dtmf Digits Or Digits Are Delayed - Cisco 3905 Administration Manual

General Telephone Call Problems

Poor Audio Quality with Calls That Route Outside Cisco Unified Communications Manager

Problem
Poor quality occurs with tandem audio encoding. Tandem encoding can occur when calls are made between
an IP Phone and a digital cellular phone, when a conference bridge is used, or in situations where IP-to-IP
calls are partially routed across the PSTN.
Cause
In these cases, use of voice codecs such as G.729 and iLBC may result in poor voice quality.
Solution
Use the G.729 and iLBC codecs only when absolutely necessary.
General Telephone Call Problems
The following sections help troubleshoot general telephone call problem.

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:
a The Ethernet cable is attached.
b The Cisco CallManager service is running on the Cisco Unified Communications Manager server.
c 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.

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.
Cisco Unified SIP Phone 3905 Administration Guide for Cisco Unified Communications Manager 8.6 (SIP)
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Troubleshooting and Maintenance