That is a feature called "post acknowledge", post acknowledge confirms to a user that the keypad signal has been received by the base station. This feature can be activated or disabled for each individual keypad. To deactivate this feature use the clear (Clr) key and then press 920 on the keypad. Or set on/off for all keypads in selected ranges via PowerCom Keypad settings function. Please reference PowerCom online help topic "Reply World Wide Keypad Settings" for more information.