Welcome to the World Tone Database, dedicated to the A-Z of international call progress tones. From here you can research tone parameters in national tone plans and hear the tones on-line.
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| Country | Tone | Frequency/Hz | Cadence/s | Audio |
| Sri Lanka | Busy tone | 425 | 0.75 on 0.75 off |  |
| Sri Lanka | Call waiting tone | 425 | 0.5 on 2.5 off | |
| Sri Lanka | Congestion tone | 425 | 0.25 on 0.25 off | |
| Sri Lanka | Dial tone | |||
| Sri Lanka | Disconnect tone | |||
| Sri Lanka | Holding tone | |||
| Sri Lanka | Intrusion tone | |||
| Sri Lanka | Number unobtainable tone | |||
| Sri Lanka | Ringing tone | |||
| Sri Lanka | Route tone | |||
| Sri Lanka | Special information tone | |||
| Sri Lanka | Warning tone | |||
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