International Telephone Busy Signal Reference 

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The Busy signal is used in Public Switched Telephone Networks to indicate that the called party is already taking another call. On most switching systems, the busy signal will be emitted until the caller goes on-hook.

Some countries use a variation of the busy to indicate that the call failed due to network routing or translation trouble and that the called number may or may not actually be engaged. These variations in the busy signal usually only alter the cadence, not the tone frequencies, and may be accompanied by or used in place of a recorded message.

Busy Signal by Country
Country Frequency Second
Frequency
component
(if used)		 Period 1 On Period 1 Off Period 2 On Period 2 Off Amplitude
Belgium 450Hz   0.15sec 0.15sec   -20dBm
France 440Hz   0.5sec 0.5sec   -20dBm
Germany 425Hz   0.5sec 0.5sec   -20dBm
Israel 400Hz   0.5sec 0.5sec   -20dBm
Italy 425Hz   0.5sec 0.5sec   -20dBm
Japan 400Hz   0.5sec 0.5sec   -5dBm
The Netherlands 425Hz   0.5sec 0.5sec   -20dBm
Norway 425Hz   0.5sec 0.5sec   -20dBm
Singapore 270Hz 320Hz 0.75sec 0.75sec   -20dBm
South Korea 480Hz 620Hz 0.5sec 0.5sec   -20dBm
Sweden 425Hz   0.25sec 0.25sec   -20dBm
Switzerland 425Hz   0.5sec 0.5sec   -20dBm
Taiwan 480Hz 620Hz 0.5sec 0.5sec   -20dBm
United States 480Hz 620Hz 0.5sec 0.5sec   -20dBm
United Kingdom 400Hz   0.4sec 0.4sec   -20dBm
This information is provided on an "AS IS" basis and has no warranty. Most countries have regulatory authorities who will have the latest specifications and compliance information.

Related Topics

International Telephone Dial Tone Signaling Reference (HTML)
International Telephone Ring-Back Signaling Reference (HTML)
Information on dialing out-of-country numbers using a computer modem. (HTML)

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[Copyright 1995,2000,2002,2004 Frank Durda IV, All Rights Reserved.
Mirroring of any material on this site in any form is expressly prohibited.
The official web site for this material is:  http://nemesis.lonestar.org
Contact this address for use clearances: clearance at nemesis.lonestar.org
Comments and queries to this address: web_reference at nemesis.lonestar.org]

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