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#16544 by jm9496
Wed Aug 19, 2009 8:09 pm
How do I measure REN for all phones on a line? Do I call the phone line and measure voltage and current when it rings to find the impedance? I suppose that would give me |Z|.

(in the US, 6930Ω resistor in series with an 8 µF is 1 REN)
#16545 by WayneDsr
Wed Aug 19, 2009 8:27 pm
REN number is usually on the bottom of every phone.
On cordless there is one number, for the base.

Wayne
#16546 by niknak
Wed Aug 19, 2009 8:35 pm
this number is only relevant if you have older, solonoid type ringers..all new phone equipment use solid state ringers with REN < 1
#16552 by jm9496
Thu Aug 20, 2009 4:38 am
WayneDsr wrote:REN number is usually on the bottom of every phone.
On cordless there is one number, for the base.

This is not related to the question asked. Please stay on topic. The question is: how does one measure REN?

I think the simple answer is this:

(1)Measure the voltage when ringing.

get something around 70-90 VAC

(2)Measure current. when ringing

get something around 10-100 mA AC. For this example, let's assume 50mA AC.

(3) measure ring frequency (or assume US standard of 20Hz)

get 20Hz in the USA

(4) plug voltage and frequency into the USA equation for REN:

(90 volts) / ((6930 ohm) + (j / (2 * pi * (20 hz) * (8e-6 F))))

(5) Calculate and get current out:

(90 volts) / ((6930 ohm) + (j / (2 * pi * (20 hz) * (8e-6 F)))) = 0.0127248411 - 0.00182649834 j amperes

(6) calculate magnitude of current/REN.

|current| = ~13mA for one REN

(7) take the measurement for line current when ringing and divide by current/REN:

50mA/13mA= 3.8 REN
Last edited by jm9496 on Thu Aug 20, 2009 5:53 am, edited 2 times in total.
#16556 by just4fn
Thu Aug 20, 2009 5:46 am
I used a scale but was fooled by it because it was in Celsius. So then I changed it to Imperial metric and now it measures REN just fine. Unfortunately It can only measure 2 REN's at a time.
#16566 by niknak
Thu Aug 20, 2009 7:18 am
...unfortunately It can only measure 2 REN's at a time...



In order to measure more than 2 RENs at a time you need a Stimpy
Last edited by niknak on Thu Aug 20, 2009 7:24 am, edited 1 time in total.
#16567 by WayneDsr
Thu Aug 20, 2009 7:20 am
REN number is usually on the bottom of every phone.
On cordless there is one number, for the base.


This is not related to the question asked. Please stay on topic. The question is: how does one measure REN?


This may have not been the anwser you were looking for, but HARDLY off topic.

I was merely trying to answer your question about REN, easy answer, look on the bottom of the phone. This question has been asked many times in this forum and "bottom of the phone" has been the solution.
Until, now, of course.....

1 REN is equivalent to a 6930Ω resistor in series with an 8 µF (microfarad) capacitor.

Wayne
#16569 by just4fn
Thu Aug 20, 2009 7:27 am
I had a stimpy but was crushed by a garbage truck.
#16570 by WayneDsr
Thu Aug 20, 2009 7:28 am
just4fn, niknak
HA HA You guys crack me up!

Wayne
#16578 by southsound
Thu Aug 20, 2009 8:30 am
The resident raccoon normally stays out of discussions beyond his comprehension but one could assume that an answer with the most formulae and decimal places would be nearer to the correct one as it is analytically self-contained. The more simplistic approach used postal scales to compare REN's and Stimpy's contains flawed logic. The basic problem with comparison of mass is that the expression and/or existence of any difference relation entails a common medium and syntax. Reality is a relation, and every relation is a syndiffeonic relation exhibiting syndiffeonesis or "difference-in-sameness". Therefore, reality is a syndiffeonic relation. Syndiffeonesis implies that any assertion to the effect that two things are different implies that they are reductively the same; if their difference is real, then they both reduce to a common reality and are to that extent similar. Syndiffeonesis, the most general of all reductive principles, forms the basis of a new view of the relational structure of reality..

Therefore, the following may be more nearly correct: :idea:
(90 volts) / ((6930 ohm) + (j / (2 * pi * (20 hz) * (8e-6 F)))) = 0.0127248411 - 0.00182649834 j amperes

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