Call Waiting Tone
A brief burst of tone interrupting phone conversation signals that you have another call waiting.

Confirmation Tone
Two bursts of tone followed by ringing or dial tone signals that the feature you want has been accessed.

Error Tone
A rapid busy signal notifies you that an unavailable feature, an incorrect access code, or a non-existent station number has been dialed. It can also signify that the call you’ve placed cannot be completed.

Flash Tone
Three bursts of tone followed by a dial tone (after you’ve depressed the Switchhook/Link function) activates Flash. This signal notifies you that the system has been accessed and you can now dial a station or access code.