Author Topic: REN - Ringer Equivalency Numbers  (Read 27199 times)

Offline dsk

  • **
  • Posts: 3794
Re: REN - Ringer Equivalency Numbers
« Reply #60 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

Offline TelePlay

  • Global Moderator
  • *****
  • Posts: 7251
    • . . . times keep changin'
Re: REN - Ringer Equivalency Numbers
« Reply #61 on: January 23, 2019, 04:26:44 PM »
     Regular Member Post

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.

Offline dsk

  • **
  • Posts: 3794
Re: REN - Ringer Equivalency Numbers
« Reply #62 on: January 24, 2019, 01:57:00 PM »
That is the book!

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


dsk
« Last Edit: January 24, 2019, 02:12:04 PM by TelePlay »

Offline HarrySmith

  • ***
  • Posts: 5970
  • 1937 302
Re: REN - Ringer Equivalency Numbers
« Reply #63 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.
Harry Smith
ATCA 4434
TCI

"There is no try,
there is only
do or do not"

Offline andy1702

  • **
  • Posts: 571
  • UK Telephone Restorer
    • Andys Shed
Re: REN - Ringer Equivalency Numbers
« Reply #64 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.
« Last Edit: January 24, 2019, 07:06:43 PM by TelePlay »
Call me on C*net 0246 81 290 from the UK
or (+44) 246 81 290 from the rest of the world.

For telephone videos search Andys Shed on Youtube.

robert_m

  • Guest
Re: REN - Ringer Equivalency Numbers
« Reply #65 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.