Any unlabeled line button on multiline telephones can be programmed with a feature for one-touch activation. See Programming MLX-10 and MLX-5 Nondisplay Telephones, Programming MLX Telephones by Using the Display, Programming ETR and MLS Telephones and Programming TransTalk MDW 9000 Telephones in this appendix for additional information about programming features onto line buttons.
Some features, such as Auto Dial, must be programmed onto line buttons in order to function. Other features, such as Privacy, are best used if programmed onto line buttons--the LED next to the line button provides visual indication that the feature is in use. The following features must be programmed onto line buttons: