Phone Does Not Recognize Dtmf Digits Or Digits Are Delayed - Cisco 8851 Administration Manual

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, 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.

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.
Cisco IP Phone 8800 Series Multiplatform Phones Administration Guide
General Telephone Call Problems
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