DIAL TONE 350 + 440 Hz CONTINUOUS RINGBACK TONE 440 + 480 Hz 1 sec on + 3 sec off DID RINGBACK TONE 440 + 480 Hz 2 sec on + 4 sec off BUSY TONE 480 + 620 Hz 0.5 sec on + 0.5 sec off DND/NO MORE CALLS 480 + 620 Hz 0.25 sec on + 0.25 sec off TRANSFER/CONF 350 + 440 Hz 0.1 sec on + 0.1 sec off CONFIRMATION TONE 350 + 440 Hz 0.05 sec on + 0.05 sec off ERROR TONE 480 + 620 Hz 0.05 sec of tone 1/0.05 sec of tone 2