An audible signal indicates an incoming call. The touchpad is a standard 12-button touchpad. Feature line buttons. You access the features and lines by non-locking push buttons. You activate all features on an ITE by pressing a feature button or by dialing the appropriate code through the touchpad.
Some telephones have feature button labels spelled out.
However, most telephones list feature abbreviations as shown in this user guide. Ringing volume control. To adjust the ringing volume on the ITE 12A, turn the knob at the lower right corner on the face of the telephone. On the ITE 12P, ITE 12S, ITE 12SD, and ITE 12T ringing volume and ringing tone controls are on the left side of the telephone. This feature is available only on models equipped with a data option board.