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Ringer equivalence number$ `7 a& Q. `/ i8 [& P4 q6 O6 I8 D2 R
http://en.wikipedia.org/wiki/Ringer_equivalence_number
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In telecommunication, a ringer equivalence number (REN) is a somewhat arbitrary number which denotes the electrical load a telephone ringer has on the line. In the U.S., this is determined in accordance with ANSI/TIA-968-B (August 2009).& A/ k' O, m: j
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REN is a United States-developed yardstick, but analogous systems exist internationally. In some countries, (particularly in Commonwealth nations), the REN is better known as the ringer approximated loading number (RAL).
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% a S: _# b9 h: @' B. r" t/ c) wIn the United Kingdom it is called the ringer equivalence number and a maximum of 4 is allowed on any British Telecom (BT) line.
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9 O7 K. Z, H9 d6 {% g8 l0 bIn Canada it is called a Load Number (LN); which cannot exceed 100. (The LN of each device represents the percentage of total load allowed).
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1 ^2 q) Q. ]$ W7 @2 Z' Y/ SIn the United States 1 REN was formerly equivalent to a 6930Ω resistor in series with an 8 µF (microfarad) capacitor. The modern ANSI/TIA-968-B specification (August 2009) defines 1 REN as an impedance of 7000Ω at 20Hz (type A), or 8000Ω from 15Hz to 68Hz (type B)., N; a G5 [7 }
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In Europe 1 REN used to be equivalent to an 1800Ω resistor in series with a 1 µF capacitor. The latest ETSI specification (2003-09) calls for 1 REN to be greater than 16 kΩ at 25 Hz and 50 Hz. |
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