Intern-Dial-Tone

The dial tone determines the sound a user hears after lifting the receiver. The "internal dial tone" is the same as the tone that a user hears at a PBX without spontaneous outside-line access (three short tones followed by a pause). The "external dial tone" is thus the same as the tone that indicates an external line when the receiver is lifted (constant tone without any interruptions). If necessary, adapt the dial tone to the use for spontaneous outside-line access to simulate the behavior of an external connection.