Classic Rotary Phones Forum

Telephone Identification, Repair & Restoration => Technical "Stuff" => Topic started by: benhutcherson on October 21, 2008, 07:21:49 PM

Title: REN - Ringer Equivalency Numbers
Post by: benhutcherson on October 21, 2008, 07:21:49 PM
Hello Folks,
I posted this in another thread, but thought it was worth some discussion on its own.

I came across the following quote in a Singing Wires back issue

"The early 500s were plagued with transmission problems, and the ringers were (and remained) less efficient than their 302 predecessors."

I know that a C4A ringer is arbitrarily defined as having an REN of 1. If we take this to be true that the earlier ringers used in 302(I forget the number) were more efficient, does this also mean that the REN is less than 1?

I'd measure it myself, but don't have the necessary power supply to make them ring(and then measure the resultant current).


Thanks,
Ben
Title: Re: REN - Ringer Equivalency Numbers
Post by: metdial on January 25, 2009, 08:17:55 AM
I just looked at an auction on ebay for a WE 500 from 1962.  The seller (who claims to have over 35 yrs. in the phone industry) makes this statement in his description: 

"The bell is not wired for current usage, this can be changed but not advised due to heavy current drain that these units have."

Is the current required for one of these old ringers really that significant? 
Title: Re: REN - Ringer Equivalency Numbers
Post by: Konrad on January 25, 2009, 09:27:37 AM
I was looking at the same listing and scratched my head.

In the 1800's a German philosopher put forth that man learns nothing from history.  Ringer Voltage is measured in RENs Ringer Equivalency Numbers.  What is 1 REN.  The voltage used by a WE 500 Ringer.  I know modern phones use much less.

Considering that you can still lease a new 500 and there are huge numbers still out there on lease this is pure cods wallop. Even the latest and greatest in VOIP will run at least two WE 500 and push the voltage through house wiring to do it. Ma Bell could ring at least 4 phones and probably more.

Title: Re: REN - Ringer Equivalency Numbers
Post by: Dan/Panther on January 25, 2009, 02:11:55 PM
I have 3, 500's set on loud, on my Frontier landline, and they will wake the dead in the middle of the night !
D/P
Title: Re: REN - Ringer Equivalency Numbers
Post by: BDM on January 25, 2009, 08:33:52 PM
I was looking at the same listing and scratched my head.

In the 1800's a German philosopher put forth that man learns nothing from history.  Ringer Voltage is measured in RENs Ringer Equivalency Numbers.  What is 1 REN.  The voltage used by a WE 500 Ringer.  I know modern phones use much less.

Considering that you can still lease a new 500 and there are huge numbers still out there on lease this is pure cods wallop. Even the latest and greatest in VOIP will run at least two WE 500 and push the voltage through house wiring to do it. Ma Bell could ring at least 4 phones and probably more.



I have five phones hooked to my VOIP modem. Ranging from 500 series down to bell boxed D1 mounts. No problems, which surprised me.
Title: Re: REN - Ringer Equivalency Numbers
Post by: Perry on January 25, 2009, 08:53:52 PM
I have 5 phones hooked up in my house, including 2 500s, and they all ring fine.
Title: Re: REN - Ringer Equivalency Numbers
Post by: Konrad on January 25, 2009, 10:27:47 PM
I'll pick up one of those 5 way splitters next time I'm at lowes and test my Vonage V-Portal and Comcast VOIP routers.  Our house is on the small side a WE 500 at one end and one WE 2500 at the other wake up the dead :)
Title: Re: REN - Ringer Equivalency Numbers
Post by: TIPandRING on January 25, 2009, 10:30:22 PM


"The bell is not wired for current usage, this can be changed but not advised due to heavy current drain that these units have."

Is the current required for one of these old ringers really that significant? 

eBay bullsh*** translation:

After 35 years of working for 3 telephone service providers taking orders and sweeping floors, I know that old phones draw current, so I'll add this into the description as the phone didn't ring when I hooked it up, and in order for me to make $ with someone complaining about misrepresentation I'll add in this in.
Title: Re: REN - Ringer Equivalency Numbers
Post by: Dan on January 25, 2009, 10:36:30 PM
302 upstairs and downstairs, 500 in living room, AE 90 in garage, and a  WE alligator print exeter in spare bedroom. Also a 2554 touchtone in basement. All ring true. I have heard 5 is the limit, but my house has so many phone jacks, I hooked up eight different combinations. They all rang, but the 302's and 352 wall phone seem to use more "juice" to me than the 500's do.
Title: Re: REN - Ringer Equivalency Numbers
Post by: McHeath on January 25, 2009, 11:45:03 PM
Yah I concur with my esteemed colleagues, this is baloney.  I regularly can turn on all my WE phones that are hooked up, 6 of them, and they will all ring.  Everysooften we come across pure weirdness on e-bay.


Title: Re: REN - Ringer Equivalency Numbers
Post by: benhutcherson on January 25, 2009, 11:58:04 PM
One 500, one 302, and one ancient oak ringer box that draws who knows how much current.

In addition, we have a cordless, a couple of cheap touch tone Trimline style phones with chirpers, a fax machine, and I think my dad even still has a dial-up modem connected. All of those things, of course, have an REN of their own.

I'd estimate us to be right at 5, if not over. Everything works fine-this is on a sort of VOIP set up, run by the cable company.
Title: Re: REN - Ringer Equivalency Numbers
Post by: mienaichizu on January 26, 2009, 12:29:13 AM
I have 2500 and a fax machine in my study, 500 in the stairs landing, a 554 in the kitchen and another rotary in the living room, 5 overall and all seems to ring fine
Title: Re: REN - Ringer Equivalency Numbers
Post by: Tonyrotary on September 19, 2009, 05:56:42 PM
While replacing the plastic fingerdial on the my wall Starlite phone I opened the case to take a peek inside. On the single bell a small sticker was placed that reads as follows. GTE REN 1.2P
             ATT REN 1.0A

It almost seems that the phone uses more power to ring on GTE lines than it did on AT&T lines? Kinda interesting. Any thoughts?
Title: Re: REN - Ringer Equivalency Numbers
Post by: JorgeAmely on September 19, 2009, 06:07:40 PM
I wonder what the A and P units are?
Title: Re: REN - Ringer Equivalency Numbers
Post by: rp2813 on September 20, 2009, 04:00:19 PM
Maybe it's what the manufacturer knew the respective telcos wanted to hear when they asked the customer for the REN information off of the phone?
Title: Re: REN - Ringer Equivalency Numbers
Post by: Tonyrotary on September 21, 2009, 08:10:45 PM
I tried looking up the info on google. Not sure what the P stood for since I could not fine anything about GTE REN numbers. But the A stood for a ringer then rang on 20hz. Then there are B ones that rang on another frequency. and so on. (on Ma Bell lines)
Title: Re: REN - Ringer Equivalency Numbers
Post by: dsk on November 18, 2009, 04:43:05 PM
I wake up this topic again, The current drain or REN will wary, I have an simple 4 line pabx, it only rings one old telephone.
The REN has never been an issue here in Norway, but the old tel-co limited us to maximum 2 telephones + one external ringer.

Looking a little at ringers. Until 1953, "all" ringers was 1000 ohms (Dc resistance) in series with a capacitor of 1 microfarad. Then we got 2800 ohms in series with 1 microfarad.  (edit to 1 mfd)

So I did some measurements today.
Since I have no telephone with known REN I had to make my own definition of 1 "REN"
The base was us ARMY TA 43 PT
All the measurements was made at 25HZ and 86 Volts.
TA 43 PT :                                                     Impedance:    9686 ohm 0r 8,9 milliamp  = 1
1000 ohm ringer in series of 1 microfarad:   Impedance:    3547 ohm 0r 24,2 milliamp  = 2,7
2800 ohm ringer in series of 1 microfarad:   Impedance:    3048 ohm 0r 28,2 milliamp  = 3,2

All later telephones has been with electronic "ringers".

dsk
Title: Re: REN - Ringer Equivalency Numbers
Post by: bellsystemproperty on November 18, 2009, 08:16:44 PM
The eBay seller is just crazy, that's all.  :D I had five rotary phones hooked (that rang) up before I got my PBX. Now, the PBX alternates the ringing across the house for an incoming call. One phone rings, then the next extension rings, and repeats back to the first, it is quite interesting, but allows me to have as many phones as I want hooked up because they aren't all drawing REN at once. I have at least ten ringing phones hooked up (I lost count), but only up to three ring at a given instant because each extension has no more than three phones.
Title: Re: REN - Ringer Equivalency Numbers
Post by: ntophones on November 18, 2009, 08:38:13 PM
What happens if you exceed the amount? Will they just not ring?
I hadn't thought of that, when I hooked up a new 302 base. I have6 phones hooked up, but, one set to not ring.
D1 with 302 base, ae40, trimline princess, an old itt (the one that doesn't ring) and 2 phones that are new and do the electronic ring. Is that too much? They all ring fine that are turned on to ring.
Title: Re: REN - Ringer Equivalency Numbers
Post by: Phonesrfun on November 18, 2009, 08:56:28 PM
I am not really sure what will happen if you go too far over.  Probably just weak ringing, and if you are on a regular phone line, maybe a trouble ticket would be kicked out at the central office for someone to follow up on.  Whether the phone company actually does follow up in this day and age, I don't know.

A typical WE 500 model phone has a Ringer Equivalence number (REN) of slightly under 1.0.  According to Ralph Meyer's book, "Old-Time Telephones", Old FCC rules were that the total of all the RENs hooked to a line could not exceed 5, but I really don't believe anyone at the phone company pays much attention unless the current drain during ringing gets to be excessive.  One thing is for sure.  5 or 6 phones all ringing at the same time can get to be noisy.

So, my guess is that if you add too many more phones, you might experience weaker ringing.  
Title: Re: REN - Ringer Equivalency Numbers
Post by: gpo706 on November 18, 2009, 09:23:00 PM
okay doaky,

I have 2 x 746's, 3 x 706's, a 554 and my 1C2 wired up  at the moment.

I get a weak ring from one of 706's, the 554 is on "off" switch, and the 1C2 rings like dandy.

So I disconnected the 1C2 (because the ring is nice but right next to my bed, and I usually find the debt collectors like to phone folks on constant backshift at 9.30am, but also it has crackle on the transmitter).

I used to have a booster but obviously the broadband provider don't like it, so sod em, I need to get a wiring loom and redo all my cables...

The REN doesn't seem to mean anything on this circuit, probably because all the phones I have are botched jobs which work and I'm frankly too scared to fiddle about with anymore.

Righty, off Sat/Sun/Mon gonna strip everything out and recable all my junk!
Title: Re: REN - Ringer Equivalency Numbers
Post by: Phonesrfun on November 18, 2009, 09:54:36 PM
dsk:

I am no expert on REN, but according to Ralph Meyer's Book, an REN of 1 is an impedance of 7000 ohms. 

I am also glad you found Colin's (oldphoneguy) information.  I once built one of his "subsets" using a resistor and a capacitor built into the base of a 202.  It worked satisfactorily for what I was using it for.

-Bill
Title: Re: REN - Ringer Equivalency Numbers
Post by: dsk on November 19, 2009, 02:41:06 AM
1 :) Thank you to Bill "sending me to" http://oldphoneguy.com/   I have been reading, and enjoyed my selves (current English?) with the downloadable pdf documents.
2 :) Whats happening if you connect too many ringers?


3  :) You may not make an exactly measurement of REN, but you may measure the current on your line, this may give you a reasonable idea of how much you put on the line. (my guess is that the only way they could test it was this way).
When you put in a extra working telephone on your line, and something starts to behave in an unwanted way, you have probably put in one too much. Remove it, and everything is OK.

 :) :) :) I believe the UK way, to split up the 1'st (master-)socket to have a 3 ringer wire may be smart, This has a common capacitor! The wiring on the telephones is then as on ringers with ground return, and the third wire is the faked ground.

dsk
Title: Re: REN - Ringer Equivalency Numbers
Post by: ntophones on November 19, 2009, 07:25:44 AM
Do you alleviate the problem by just turning off ringers, then? Or, do you have to disconnect the phone?
It won't hurt your wiring, will it?
Title: Re: REN - Ringer Equivalency Numbers
Post by: dsk on November 19, 2009, 08:10:05 AM
Turning off the ringer will on some telephones only affect the sound, and will not help.
On others it is a switch disconnecting the ringer. This will help.
You just have to try.

I have never experienced anything damaging my telephone line by putting in odd things in the circuit.

Some adapters from ISDN, or internet, may dislike old ringers, and rotary dials, and collapse.

My line has been ruined once, when a stroke of lightning hit the pole next to the house.
The fuses, and surge protection, was just evaporated! (still burnmarks on the wall 20 years later)
I had 3 telephones, 2 containing electronics, and a 1934 telephone, When I opened my 1934, the yoke was thrown out of its hings. After putting the yoke back, the telephone was in OK again. More trouble wit the other two (--> trash can). :)

dsk
Title: Re: REN - Ringer Equivalency Numbers
Post by: ntophones on November 19, 2009, 11:31:04 AM
Wow! They just made great phones back then, eh? :)
Title: Re: REN - Ringer Equivalency Numbers
Post by: dsk on October 14, 2010, 08:51:33 AM
Hi, I have problems with determining an approx ren no of Norwegian telephones.
The only American telephone I have is an old TA43PT. (http://www.myinsulators.com/commokid/telephones/ta43pt_9.jpg).

If I knew the REN no of this, I could make a simple circuit and measure the current at e.g. 20Hz and make a factor telling the approx ren no.

At least that is what I think????


Tank you.

dsk
Title: Re: REN - Ringer Equivalency Numbers
Post by: dsk on October 23, 2010, 02:12:02 AM
I got a hint one place to substitute one REN with the load of 7 kiloohms, another place I was told 70.7 millamps at 75 V 25Hz.
So I have measured, at 75 V 25Hz:
  ;) The Ta43TP 7.630 mA = 0.7 REN
  ;) The German Amtsanschliesser 28.5 mA = 2.7 REN New data with right capacitor: 17.1 mA =1.6 REN! 
  ;) Typical Norwegian 2.8 kOhms ringer in series with 1 uF (EB model 1953) 12.4 mA = 1.2 REN
  ;) Typical Norwegian 1 kOhms ringer in series with 1 uF (most before 1953) 22.3 mA = 2.1 REN

So if the traditional Norwegian ringer is approx 2-2.5  REN it the limit of 2 ringer gives quite equal limitations as your max at 5 REN.

dsk
Title: Re: REN - Ringer Equivalency Numbers
Post by: bingster on October 23, 2010, 02:35:19 AM
Wow. The 2.7 REN of the German set is surprisingly large.
Title: Re: REN - Ringer Equivalency Numbers
Post by: dsk on October 23, 2010, 03:32:04 AM
I am not sure why, but German ringing-voltage is 60V but Norwegian is 90V

This testing was done at 75V 25Hz.

dsk

Edit:
Looking at the Amtsanschliesser 33 ( Amtsanschließer 33   (http://wendtland.org/Amtsanschliesser.html)) the capacitor was wrong, 2 μF instad of 1 μF.
New measurement: 17.1 mA =1.6 REN!  
Thanks for getting me using my brain again!  :D

I have always been looking at the coil resistance of ringer, but this ringer has DC resistance of 380 Ω !!

I have still an idea of this resistance is a measure of how sensitive the ringer is, but the greater current, and no windings the more sensitive it should be so  ???


dsk
Title: Re: REN - Ringer Equivalency Numbers
Post by: DavePEI on June 03, 2012, 06:40:36 AM
I wonder what the A and P units are?
Probably the P measurement is Peak, and the A is Average.

Dave
Title: Re: REN - Ringer Equivalency Numbers
Post by: dsk on June 03, 2012, 08:14:12 AM
To increase the confusion I come with a new theory.
REN = Ringer Equivalent Number in the bell system this will equal the most common ringer at the time introduced, the ringer in a std. 500 telephone.
Later this has been the base of an international standard. 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).

Before this different countries or telephone companies was making their own standards if the want.

Here i  Norway, the rule was max 2 ringers on a line. When we measure a Norwegian ringer against the 500 telephone the current consumption is nearly 2.5 times the 500, and should be deemed to be 2.5 REN ringers.


Whats the point of this strange unit? REN!
It was used to define the max allowed ringer load at a line still working well. At a short line The current will be higher, and the exchange may see the high load as someone going offhook, On a long line with high voltage drop, it should still be power enough to run a sudden number of ringer motors.

My 1948 PAX indicates off hook when i load it with more than approx 3 REN. (Short lines)
This problem indicating off hook would never happen if I used the British system with master socket and one common capacitor.

What about the suffix? Just guessing: A for ordinary frequency ringers 20Hz (25 in Europe) All other letters indicates non std frequency.
Title: REN levels
Post by: Babybearjs on September 20, 2012, 10:36:44 PM
OK, here an easy one...... I have 4 phones in my home, 1 in the bedroom, 1 in the kitchen, 1 in the livingroom and 1 in the front den..... now, why do my phones all fail to ring right when there is a call???? in the bedroom, I have a WE 307C.... in the Kitchen I have a 444E, in the livingroom I also have a 444E... and in the front den I have a 2564.... the phones all start to ring in the first ring, and then just the kitchen extention sounds and the rest are quiet.... any idea why???
Title: Re: REN levels
Post by: TelePlay on September 20, 2012, 10:58:32 PM
Try disconnecting one phone and see if the remaining 3 ring. If the three don't ring, disconnect another and see if the remaining 2 ring. At best, COs provided up to, I think, about 5 REN but with modern phones needing anywhere from .1 for external powered digital phones to .8 for analog phones, your CO may have reduced power to you house. Seems 4 phones, assuming each of your phones is 1 REN, is too big of a load for what is being sent to your house. Your phones may also have 1.25 or some other higher REN which in total overloads the power available on your POTS line.

I'm sure others who know more than I will clean up this thought with better facts.
Title: Re: REN levels
Post by: twocvbloke on September 20, 2012, 11:15:21 PM
There are usually other factors to consider, the distance to the telco's hardware, the age of the copper wires to you house, the quality of connections to your house, and the phones themselves which may not be 1REN each, so could be overloading your line...

One option would be a REN booster, giving your line some more juice supplied by your mains power, or the other option, a small phone system like the Panasonic KX-T308 or T616, providing 8 or 16 extensions respectively, along with 3 or 6 incoming lines... :)
Title: Re: REN levels
Post by: dsk on September 21, 2012, 05:34:19 AM
The ren load is the easiest thing to test, just try to reduce the number of ringers connected.
If 3 phones rings, you know the answer.
It is several ways to reduce that load. The most common is serial resistors, who just consume energy to heat the resistor, and you get even weaker ringing.  One of the "forgotten" ways:Wire 2 of the telephones for grounded ringing. One for tip to ground, and one for ring to ground, but you do not ground them, just connect the ground wire from the 2 phones together, then you get 2 ringers in series, a little weaker ring, but better than using resistors.

If the 2 ringers in series are different one will ring louder then the other.

dsk
Title: Re: REN levels
Post by: poplar1 on September 21, 2012, 07:45:01 AM
Have you also put the bias spring in the low position on each ringer?
Title: Re: REN levels
Post by: HowardPgh on September 21, 2012, 09:55:04 AM
How is REN determined?
Does one REN=X milliamperes?
Howard
Title: Re: REN levels
Post by: dsk on September 21, 2012, 10:38:13 AM
Different telcos has different standards. The most used definition is from Wikipedia:

A ringer equivalency number of 1 represents the loading effect of a single "traditional" telephone ringing circuit, such as that within the Western Electric Model 500 telephone. Note that the REN of modern telephone equipment may be significantly lower than 1: as a rough guide, externally-powered digital-ring phones may have a REN as low as 0.1, while modern analog-ring phones (where the ringer is powered from the phone line) typically have a REN around 0.8.

In 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).

The measurement in milliamps will not be linear, but; when I measure the load at my P.O.T.S. line I get a voltage of approx 95V with no load, and a mA reading of approx 10 mA per REN in the range from 1-4 REN. 11-12 mA at one REN and 39-40 at 4 REN.

This reading will depend on the line and exchange resistance and impedance. The wire length to the exchange are approx 7-8 hundred meters.  

dsk

Some new measures here:
Title: Re: REN - Ringer Equivalency Numbers
Post by: dsk on December 20, 2012, 03:28:33 AM
I have done some measuring at my POTS line, and tested 2 well known phones.
My conclusion will not be any scientific break trough  :) just again confirming the impossibilities of masuring REN no at the line.

The picture tells about the result, my conclusion is again, we cant measure this because of the line complexity. The length and the exchange equipment will make problems for this measurement. The only way to tell how much load your line has capacity of is to increase loud until you get problems, and then reduce to its working well.

A hint will be if the ringing current exceeds twenty-something mA, or the ringing voltage drops considerably under 60V you may expect problems, whatever happens first.

dsk
Title: Re: REN - Ringer Equivalency Numbers
Post by: unbeldi on December 20, 2012, 08:49:21 AM
.
Title: Re: REN - Ringer Equivalency Numbers
Post by: dsk on December 20, 2012, 09:53:10 AM
Complex or not  ??? At lest its no easy way to know what I may put on my line, and whats happening before i just test it. I have a wide range of telephones, from the typical German 600 ohms +1 uF ringer to modern ones. Changing one telephone with another may result in different results. To high load may result in false off hook detection, to big difference in the ringers, may cause one to be weak, but others still rings with a loud ring.  My simple REN no calculation of the Standard telephone is simply done by ringing a 1 REN ringer at 25Hz at 70V and measuring the current (2500 telephone), measuring the current on the unknown ringer and determine the factor.

The old Norwegian rule was a max of 2 telephones on one line, by my simple calculations/measurement the typical ringer was about 2.5 REN (This has never been used terminology here). Usually it was no problem adding the 3'rd ringer, but don't tell anyone, and of course you payed extra for renting all extra equipment. The extra ringer, often put outdoors did usually not have a bias spring, so you would always know if someone was dialing.

dsk
Title: Re: REN - Ringer Equivalency Numbers
Post by: old_stuff_hound on December 20, 2012, 11:49:20 AM
Not to hijack, but has anyone measured what the REN of a 302 is?

Asie: how does one search this forum for complete words only (i.e. so that the search for 302 REN doesn't return posts that happen to contain words that have the three letters "ren" in them somewhere....)?
Title: Re: REN - Ringer Equivalency Numbers
Post by: dsk on January 03, 2013, 01:00:38 PM
I have got some help from Ralph O Meyer, The writer of "Old-Time Telephones!"

I really hope I understood his hints, at least I have designed this circuit:
(http://www.classicrotaryphones.com/forum/index.php?action=dlattach;topic=7640.0;attach=44490;image)

Based on this I did some measuring and ended up with some values.
The values are based on measuring one single phone of each kind, and if we include some inaccuracy, the values should just be indicator within a range of about +/- 10% (I hope)
Since my ringer supply was 25Hz, the 1 REN impedance had to be 8000 ohms.
(http://www.classicrotaryphones.com/forum/index.php?action=dlattach;topic=7640.0;attach=44493;image)

One of my conclusions are: The ringer resistance does not tell my anything about the REN.
Another may be to add another capacitor in series, or change to a smaller capacitor to reduce the load without loosing to much of the power.

dsk
Title: Re: REN - Ringer Equivalency Numbers
Post by: dsk on January 06, 2013, 08:30:09 AM
Still my readings gives some strange results.
http://tinyurl.com/azpxtt4

I'm definitely not sure whats happening when changing capacitor, and greater capacitor gives lower load, and vise versa.

dsk

Title: Re: REN - Ringer Equivalency Numbers
Post by: Phonesrfun on January 06, 2013, 01:22:01 PM
Dag:

Your measurements seem to show a REN of .76 for a WE 500, where I have always thought that the 500 was somewhere at about .9, rounded to 1.0.  Could that difference be due to frequency?  In Norway, you apparently have 25 HZ ringing current.  perhaps I will answer my own question by going back and looking at what Ralph says in the book.  You are more up to date on the reading than I am.
Title: Re: REN - Ringer Equivalency Numbers
Post by: dsk on January 06, 2013, 03:40:38 PM
You are right, I have used the setup described by Ralph O Meyer, but used 25HZ. This is compensated by using a load of 8000 ohms as 1 REN instead of 7000 at 20Hz.
What I measured is true, but the the power-supply is frequency divider, how clean the Sinusoid current actually are is unknown. The phones of equal type may also wary quite much, so the values may be just an indication.

All help and hints are welcome.

dsk
Title: Re: REN - Ringer Equivalency Numbers
Post by: AE_Collector on January 06, 2013, 08:07:08 PM
I have merged up several "REN" discussions here now. (NOT) Surprisingly, "dsk" seems to have been involved in most of them if not all of them!

Terry
Title: Re: REN - Ringer Equivalency Numbers
Post by: dsk on January 07, 2013, 04:31:14 AM
 :D REN is an interesting unit. Seems quite logic, just like CANDLEPOWER. Wen it comes to real practical life, its not simple at all.  D.c. resistance has been used, and many collectors has used resistors to adjust the resistance of the circuit.
At the moment all this seems to be indications. When you run different ringers with equal data, some are ringing more easy than others.  Traditionally the high ohm ringers were used at long lines with weak signals, but the mechanical design may be important.

Any conclusion? Not exactly, I have much more to learn.

dsk

Some thoughts added later:

The force from an electromagnet is described here: http://tinyurl.com/bku87lz
The frequency is no issue in those consideration, but if the ringer is made for approx that frequency we could optimize the sensitivity of the ringer, for later make it work at the lowest possible electric load. The easy movement is important, a shorter gap (less way to move for the clapper)
This will give a softer ring, with less sound volume, but I have noticed the still loud volume.
This has of course to be followed by adjustment of the gongs. Positioning the gongs as near as possible to each extreme rest position of the clapper, but not touching works well.
This is not so easily adjusted at single coil ringers, as older twin coil ringers. Frequency ringers are far out of this, because the resonant frequency is tuned in to all parts of the ringer.

If you want to many ringers, you may have to live with bell tinkling, and skip the using of the bias spring.
Title: Re: REN - Ringer Equivalency Numbers
Post by: George Knighton on January 07, 2013, 08:11:46 AM
If you want to
  • many ringers, you may have to live with bell tinkling, and skip the using of the bias spring.
There's gotta be something wrong.  That's just waaaaay too simple an answer!
Title: Re: REN - Ringer Equivalency Numbers
Post by: GTE Rick on January 12, 2013, 05:41:29 PM
Did Bell & GTE calculate REN Differently?  I was looking at the bottom of some GTE/AE phones and saw these stickers on the bottom
Title: Re: REN levels
Post by: Babybearjs on February 09, 2013, 01:02:21 AM
problem solved.... bias springs in high position. all phones are ring now. disconnected ringers on 2 of them, too loud!
Title: Re: REN - Ringer Equivalency Numbers
Post by: dsk on December 13, 2015, 03:52:37 PM
This document could be of interest.   http://www.ti.com/lit/an/slua060/slua060.pdf
Here they design a ringer power supply at 125mA and states it to be 10 REN.

dsk
Title: Re: REN - Ringer Equivalency Numbers
Post by: markosjal on December 26, 2017, 12:57:09 AM
I just posted this
http://www.classicrotaryphones.com/forum/index.php?topic=19475.0

As it seems somewhat relevant to this thread I thought maybe someone from this thread could enlighten me

My question is not about RENs as much as high impedance ringing.

My Grandstream HT503 will not ring an AE Styleline nor a WE Princess 2702BM.

IT WILL ring Mexican Indetel models and Mexican Ericsson Models. Both of these have .33mF Capacitors

Mark
Title: Re: REN - Ringer Equivalency Numbers
Post by: andy1702 on January 21, 2019, 12:35:19 PM
The UK rule is a home system must only have phones connected that add up to no more than 4 REN. This came in during the early 1980s when people started to buy their phones and also when we changed over to plug & socket, enabling subscribers to easily wire their own extensions so having more than one phone in the house for the first time. The most common phones around at the time were the GPO 7xx series. These had 2x 500 ohm coils in the ringer and an alleged REN of 4 (so you couldn't keep them and also have an extension. But the later 8746 (a 746 pre-configured for plug & socket on delivery) only had a REN of 1. This was because it had the 2x 500 ohm coils replaced with 2x 2000 ohm coils, so about 4000 ohms resistance in total.

What we do now is to add a 3.3k ohm resistor in series with the bell coils of old sets with 2x 500 ohm coils. This gives a total of about 4,300 ohms, which is near enough! The resistor does weaken the bells of the 500 ohm coils slightly, but they still ring.

If teh value of REN is the same all over the world and a 500 set has a REN of 1 (which is what I've always understood to be the case) then I'd assume the 500 is about 4000 ohms. This is way below the 7000 ohms some people have quited here as 1 REN, so maybe that explains why more 500s work than officially should.
Title: Re: REN - Ringer Equivalency Numbers
Post by: poplar1 on January 21, 2019, 03:24:14 PM
DC resistance of a C4A ringer (in a 500 set or other) is 3650 ohms.
Title: Re: REN - Ringer Equivalency Numbers
Post by: dsk on January 22, 2019, 01:23:04 AM
As stated by someone earlier in this thread, the REN load is difficult, the impedance is OK, but the impedance change depending on other parts of the system, sometimes even whats inside the ATA.  The idea about adding a resistor is a safe way of rising the impedance with (almost) equal the resistor value. The only drawback is the power reduced by the resistor is turned to heat.  Putting in a capacitor may be better, but will absolutely be more sensitive to changes in other parts of the system. It is not a safe way to calculate the right value of the capacitor, so you have to try.  So far my experience has turned out well by using a capacitor of 1μF or 0.68μF rated 200V or more.

On a single ringer (2*500 ohms) roughly measured the REN load was about 2.04 (Z=3429ohms)with a 1μF capacitor, adding one more in series = 0.5μF the REN load was only 0.78 (Z=8926ohms)  but different 1000 ohms ringers has different characteristics so this makes no safe rule!  Only once I have experienced that the REN load falls with a higher value of the capacitor, and that makes me think; did I get the correct readings?

dsk
Title: Re: REN - Ringer Equivalency Numbers
Post by: dc4code on January 22, 2019, 03:08:12 PM
I was looking at the same listing and scratched my head.

In the 1800's a German philosopher put forth that man learns nothing from history.  Ringer Voltage is measured in RENs Ringer Equivalency Numbers.  What is 1 REN.  The voltage used by a WE 500 Ringer.  I know modern phones use much less.

Considering that you can still lease a new 500 and there are huge numbers still out there on lease this is pure cods wallop. Even the latest and greatest in VOIP will run at least two WE 500 and push the voltage through house wiring to do it. Ma Bell could ring at least 4 phones and probably more.

Not true.

It depends on the ATA/VG Device, A lot of enterprise-grade Analog VoIP Equipment will ring 5 (or more) WE500's. I even have one that does this AND Supports pulse dialing too!

It just depends on the equipment it is not 'VOIP' that is literally just a set of protocols! It depends on the SLIC Chip inside of the Analog Gateway equipment.
Title: Re: REN - Ringer Equivalency Numbers
Post by: Jim Stettler on January 22, 2019, 04:05:28 PM
Not true.

It depends on the ATA/VG Device, A lot of enterprise-grade Analog VoIP Equipment will ring 5 (or more) WE500's. I even have one that does this AND Supports pulse dialing too!

It just depends on the equipment it is not 'VOIP' that is literally just a set of protocols! It depends on the SLIC Chip inside of the Analog Gateway equipment.
Please add links and photos of the equipment you you are referring to.
Otherwise this post will be deleted as useless.
Thanks,
GM
Title: Re: REN - Ringer Equivalency Numbers
Post by: andy1702 on January 23, 2019, 03:03:52 PM
Well it seems from what I've gathered from this thread that at least the US and UK have a very similar definition of what 1 REN is. If  a phone's bell coils have a value of about 4000 ohms it's REN = 1. If it's 1000 ohms then it's REN = 4. So logically 2000 ohms would be REN = 3 and 3000 ohms would be REN = 4.

My understanding is that for UK approved equipment at least, any equipment such as ATAs etc has to be able to power an output with a maximum of 4 REN hanging of it.

I have to say i've never had any problems with the phones I've plugged into a given line. the only time I've noticed weak ringing is if I've added a resistor to a phone I shouldn't have by accident. I did this with a US 554 once before I knew better and the bell clapper would hardly move. There was a fairly well known website that said I had to add the resistor. It just goes to show you shouldn't believe everything you read online! I now only fit resistors to old Uk phones as necessary and would never fit one to a US 5xx series.
Title: Re: REN - Ringer Equivalency Numbers
Post by: dsk on January 23, 2019, 03:26:32 PM
REN is the most difficult and un-logical value I have tried to measure, at least according to the old definition of being the number of ringers equal to a Western Electric 500 telephone.
The later specification of a sudden impedance at 20Hz (25Hz in UK) is much more logical. 
Here in Norway they only specified max 2 ringers (delivered by the monopoly) 
Of course on extremely long rural lines this was max, but in urban areas you could probably make it 4.  I have later measured some REN loads according to the procedure in Ralph Meyer's book.  These ringers was often about 2 US REN.

Simplifying to ohmic values as Andy do are not completely reliable, but gives a pretty good idea of whats right. The capacitor size and the match between the capacitor and the coil is actually important to get an exact reading. 

On the other hand, the hunch from Andy may be good enough to make a system working. If it is working... it may be good enough.

dsk
Title: Re: REN - Ringer Equivalency Numbers
Post by: TelePlay on January 23, 2019, 04:26:44 PM
     Regular Member Post (http://www.classicrotaryphones.com/forum/index.php?topic=20151.msg206412#msg206412)

I have later measured some REN loads according to the procedure in Ralph Meyer's book.

Is this the book you used? If not, please post the title. Thanks.
Title: Re: REN - Ringer Equivalency Numbers
Post by: dsk on January 24, 2019, 01:57:00 PM
That is the book!

My measurements are collected here: https://goo.gl/yxfWg5


dsk
Title: Re: REN - Ringer Equivalency Numbers
Post by: HarrySmith on January 24, 2019, 02:19:24 PM
I have a phone that is featured in that book! A few years back I was searching for a Black WE 1500 to add to my collection and Ralph offered me his. I got it pretty cheap too. IIRC it is on page 82. I am at work right now so I can't pull out my book to double check. If I am incorrect I will change it later.
Title: Re: REN - Ringer Equivalency Numbers
Post by: andy1702 on January 24, 2019, 02:55:51 PM
REN is the most difficult and un-logical value I have tried to measure, at least according to the old definition of being the number of ringers equal to a Western Electric 500 telephone.

The later specification of a sudden impedance at 20Hz (25Hz in UK) is much more logical. 

Here in Norway they only specified max 2 ringers (delivered by the monopoly) 

Of course on extremely long rural lines this was max, but in urban areas you could probably make it 4.  I have later measured some REN loads according to the procedure in Ralph Meyer's book.  These ringers was often about 2 US REN.

Simplifying to ohmic values as Andy do are not completely reliable, but gives a pretty good idea of whats right. The capacitor size and the match between the capacitor and the coil is actually important to get an exact reading. 

I can confirm my guestimate about the REN values definitely works for both UK and US phones here in England. I have a mixture from both sides of the pond in use here all the time.

dsk

One complication here is that BT in their wisdom decided every house should have a "master socket" which wouldbe sited where the drop cable comes into the property and this socket would have a capacitor inside it, effectively replacing the capacitor inside the phone. They say you can hang up to 4REN off this system using extensions, which is ok. However I'm using a Revelation PBX, which means each extension from the revelation has it's own master socket which a phone or phones plug into. I've always assumed I can plug up to 4REN into each extension master socket. So if I wired up 10 extensions with master sockets and all the phones were 1REN each, I could run 40 phones! That's what i've assumed, but now I'm questioning my own logic there. I may have to do some experimenting.  :D

On the other hand, the hunch from Andy may be good enough to make a system working. If it is working... it may be good enough.
Title: Re: REN - Ringer Equivalency Numbers
Post by: robert_m on January 24, 2019, 03:19:59 PM
Most Bell Comapnys had REN value of 5, so would effectively run 5 500 sets without issue, VoIP youd have to look at what the ATA provides on REN, generally most I've seen are REN 2 that mean 2 500, and in some cases 2500 sets (the old mechnical ones) now this does not address line loss or a non Bell system, and as the gov screwed up the telco, and bell not around anymore, well its upto the provider to decide, but normal BELL Companys provided a REN of 5, and most sets after the 80 would tell your the REN value, if not Bell System, not sure Bell ever marked them till the gov broke them up.

To other opters points YES ATT Consumer Lease Products (Now QLT) still allows leasing of triditional 500 sets, as not all telco have eliminated rotary dialing, and when used woth many big PBXs att usetoo manufacture like system 25, system 75, Merlin 1030/3070 it handled 10 500 sets per POTS line card, but did do latched ringing 1/2 would rig, then the other half i dont recall the exact numbers, and you had to attach the external ring generater transformer.  It (at least the standard one was REN 10, I suspect as the pots cards were 10 stations)

Hope some of my post is useful.