Cisco Unified IP Phone 7900 Series

Field Notice: CP-7920 Speaker Failure Results in One Way Audio

June 25, 2004

Products Affected


Top Assembly Part Number



Problem Description

Due to a manufacturing problem, one way audio may be experienced when using a CP-7920 wireless telephone. A short circuit may occur in the speaker wiring on the CP-7920 which results in no audio being heard through the telephone ear piece.


The contact of a speaker spring with the Printed Circuit Board (PCB) may cause a scratch on the PCB. This may result in a short circuit between the speaker spring and the PCB. Manufacturing tests found the failure rate of effected units to be 0.93%.

Problem Symptoms

Due to a short circuit, the customer will not be able to hear any audio through the ear piece. Pressing on the speaker in the ear piece may temporarily fix the problem and can confirm the one way audio problem is being caused by the telephone.


There has been a change in the manufacturing process to rotate speaker spring 90 degrees so the contact area is away from the PCB. Due to the low failure rate, only telephones exhibiting this failure in the field should be replaced.


To follow the bug ID link below and see detailed bug information, you must be a registered user and you must be logged in.



CSCed93344 (registered customers only)

7920 Speaker failure results in one way audio

How To Identify Hardware Levels

How to determine if the product is effected by this notice:

Serial Number:11 digit - LLLYYWWSSSS



WW-->34 (solution phase in date August 18)

SSSS-->series number

The solution phase-in Serial Number is AMB0734SSSS (from week 34). Products before this date may be effected.

For More Information

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods:

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