Click the keys or type on your keyboard to synthesize standard Dual-Tone Multi-Frequency (DTMF) telephony signals.

Play loops representing standard call routing signals and telephone cadences.

Dial Tone 350 + 440 Hz (Continuous)

Busy Signal 480 + 620 Hz (0.5s On / 0.5s Off)

Ringback Tone (Audible) 440 + 480 Hz (2.0s On / 4.0s Off)

Reorder / Fast Busy 480 + 620 Hz (0.25s On / 0.25s Off)

Call Waiting Alert 440 Hz (0.3s On / 9.7s Off)

Receiver Off-Hook (ROH) 1400+2060+2450+2600 Hz (0.1s On / 0.1s Off)

Enter any phone number to parse and decode its country origin, area code location, format standard, and type.

Phone Number

Common North American Numbering Plan (NANP) Vertical Service Codes used on analog lines, PBX setups, and VoIP adapters.

Code	Service Name	Description & Cadence Behaviors

Standard frequency specifications for precise network tone plans (North American Precise Plan standard).

Signal Type	Frequency Combo	Volume Level	Standard Cadence Description
Dial Tone	350 Hz + 440 Hz	-13 dBm	Continuous tone until first digit dial input.
Busy Signal	480 Hz + 620 Hz	-24 dBm	0.5s On, 0.5s Off. Repeated cycles.
Ringback (Audible)	440 Hz + 480 Hz	-19 dBm	2.0s On, 4.0s Off. Repeats until answer.
Reorder (Fast Busy)	480 Hz + 620 Hz	-24 dBm	0.25s On, 0.25s Off. Signals network congestion.
Call Waiting Tone	440 Hz	-13 dBm	0.3s beep, silence for 9.7s. Overlaid on active call.
Off-Hook (ROH Howler)	1400 + 2060 + 2450 + 2600 Hz	Dynamic (High)	0.1s On, 0.1s Off. Pulsed sweep to alert of open receiver.