Ring Patterns

North America

The following is a list of commonly used ring patterns (or cadences to use the techno-jargon) in North America (defined in ANSI T1.401-1988 section 5.4.2). It uses a 20Hz frequency and voltage depends on distance from the central office (exchange) and will vary from 40 to 150V rms.

Name	Pattern/Cadence
Ringing (Code 1)	2 sec on, 4 sec off, repeating
Coded Ringing (Code 2)	1 sec on, 1 sec off, 1 sec on, 3 sec off, repeating
Distinctive Power ringing	Short (200 - 500ms), long (800 - 1000ms), short (200 - 500ms) in a 6 second period, repeating
Special ringing	two short (400 - 500ms) long (800 - 1000ms)

Notes:

REN - is Ringer Equivalence Number and defines the number of standard AT&T 500 series telephones (500 set) that can ring simultaneously. This values is normally 5 but can lie in the range 3 - 5.

Europe

The European stand ring pattern (or cadences to use the techno-jargon) is shown below (defined in ETSI prTS Interface Spec V0.0.2 (2004-11) TR41.1-05-02-010 / TR41.1.1-05-02-006 ). It uses a 25Hz (some operate at 50Hz) frequency and voltage depends on distance from the exchange) and will vary from 35 to 100V rms. This is the harmonized standard and many countries may have local variants.

Name	Pattern/Cadence
Normal Ringing	1 sec on, 4 sec off, repeating

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Ring Patterns

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