How many phones on the "phone" port?

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Re: How many phones on the "phone" port?

Post by TonyB » Mon Apr 06, 2009 10:23 pm

Within this PDF, I found this language:

The REN is used to determine the number of devices that may be connected to a telephone line. Excessive RENs on a telephone line may result in the devices not ringing in response to an incoming call. In most but not all areas, the sum of RENs should not exceed five (5.0).

Interesting. The phones in our 2 bedrooms and kitchen have what seems to be a pretty high REN of 1.08. So, if the ringer is turned-off, wouldn't that lower the REN? No need for all of them to ring when we can hear one or two...

Also, correct me if wrong, exceeding an ideal REN number seems to only impact a phone ringing? That's important of course, but wondering if it impairs the quality of the call though...

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Re: How many phones on the "phone" port?

Post by Soundjudgment » Fri Apr 10, 2009 5:42 am

The scare of 'REN' (ringer equivalence... or bell-current) harkins back to the ancient days of Ma Bell mechanical-ringers. Those old phones had NO electrical current covering their operation, save for the voltage and current delivered on the wiring coming from their Central Office. It took some hefty voltages to RING those clangers in the bells. And it was always important to make sure that too many of those style phones did not load down any one phone-line without external electrical-power to back them up.

Nowadays this is not much of an issue, because most every plastic telephone in existence these days care little to get their power from the old in-house copper telco-wiring. These phones simply come with separate AC/DC transformers (which plug from the base... into the AC Mains separately) and provide all the operational current needed for both phone-electronics and the chirpy 'ringer-tone' they sport to announce an incoming-call.

There are still inexpensive phones being sold today that get only the current from the RJ11 jack which attaches them to the phone-grid. This is the type of phone that still relies on the RJ11 TEL connector to operate with all their features (battery/dial-tone/bell-ringer) intact. Hence they post an REN on their sticker or base, so the user knows how much current these phones expect to draw on the in-home copper-grid for normal use.
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Re: How many phones on the "phone" port?

Post by ginmn » Sat Feb 08, 2014 11:09 am

This question has not been answered. Great history, but for those of us who will use our household phone outlets and like having a "older" corded phones, what is the REN output for the Ooma Telo? I seem to have an older phone that doesn't "ring" but rather deeps somewhat awful sounding noise given the REN line load. Just interested in knowing what I should look for when purchasing new devices.

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Re: How many phones on the "phone" port?

Post by murphy » Sat Feb 08, 2014 11:17 am

The Telo supports a total of 5.0 REN.
Any phone purchased today will have a REN that is less than 1.
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Re: How many phones on the "phone" port?

Post by lbmofo » Sat Feb 08, 2014 1:09 pm

I guess a lot of new phones are 0.1 REN even viewtopic.php?f=2&t=16016&start=10#p111739
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