AASTRA 6700i series, 9143, 9480i, 9480i CT SIP Administrator Guide EN - Manual (Page 344)

41-001343-01 Rev 03, Release 3.2.2 5-67
Aastra Web UI
1 Click on Basic Settings->Preferences->General.
2 Enable the "Suppress DTMF Playback" field by checking the check box.
(Disable this field by unchecking the box). Default is enabled.
3 Click to save your settings.
You must restart your IP phone for the changes to take affect.
4 Click on Operation->Reset.
5 In the "Restart Phone" field click to restart the IP phone and apply the changes.