The problem might be due to poor connection between the headset and the phone itself. Ensure that the cord is securely connected at both ends. If the cord is connected, and the problem has not been fixed, you need to replace the cord. If the problem still persists, it is due to an issue with the headset itself. Refer to the "AT&T Corded Telephone Headset Replacement Guide" for further information. If you want to know more detail, please refer to [[ATT CL2940 Troubleshooting|Troubleshooting page]]