How many phones? 6

[summoner]

My buddy is having his home built and cat5 run to each room for phones and data. I'm offering him a hand on installing/terminiating the cables. He has 10 phone drops ending at the basement panel where the phone line enters the house from the pole. My plan is to use a 66 block to hook these 10 rooms to the one phone line. Is this too many phones for one line? Whats the max amount of phones one phone line can support at once? Thanks

 

[wires]

My feeling is that it is easier to use a 110 blocks for this sort of application. Simply snake a pair across the pairs on the 110 where the phones are and punch it down with the non-cutting end of the blade.

110's are easier to label and easier to "read" for a novice.

The maximum number of phones on a line depends on the phones and the quality of the subscriber loop. It is extremly unlikley that there will ever be more than 2-3 extentions off hook at the same time so talk current is not much of a problem. The problem is when they ring, which they all will do if they are connected. If you look at the bottom of a modern phone instrument you should find a REN number. This is the Ringer Equivalency Number and by adding together all the REN of the phones you can compute the total "ringer load" that the Central Office will see when the phones ring. Depending on the phone company the maximum number is between 3 and 5 REN. If you exceed the phone companies maximum REN then you will start to have problems with the phones ringing.

Of course you can turn the ringers off on some of the phones to reduce the total REN.

Just because you wire 10 jacks you don't have to plug in 10 phones.

 

[AvayaNovice]

This may not be correct, but don't newer telephones which use digital ringers actually get their power from the AC adapter they use, and only use the ring level voltage to detect when to make a ring, thereby reducing the load?

 

[lopes1211]

If that is the case, it would reduce the load of that phone but the manufacter would account for that in their REN for that particular phone. The same concept of adding up the REN's would still apply. The phone with the AC adapter might just have an REN of .1 instead of .5 for a more traditional phone.

-CL

 

[skip555]

i beleive the telco needs to probide 10 ren which used to be a issue in the days of the electromechanical ringrs (500 / 2500 sets)

with todays electronic ringers with low draw its really not much of a issue.

 

[summoner]

Thanks for the information guys. Much appreciated.

 

[mdeeves]

isnt ringer current still ringer current?

it has been my understanding that you are pushing it if you add more than 4-5 phones on one line.

The "ring" signal is a 90-volt AC wave at 20 hertz (Hz).
This is from howstuffworks.com.

when you go off "hook" to answer a ring you tell the co to stop ring current and "switch" to talk path current. (same as dial tone -48VDC.) switch + hook = "switch hook".

So when you add too many phones all looking to eat up that 90 volts eventualy the demand becomes greater than the supply and no phone rings.

at least that is what i think. but if you ask my wife she will tel you that what i think and a dollar will buy you a cup of coffee.

Mike

 

[jkupski]

mddeves:

Voltage is not a measure of current.

 

[mdeeves]

jkupski,

correct voltage does not measure current.

but the amperage is and has to be low. (too much juice on 24 or 24 G telephone wire = exploding cable)

And with the ringers on the phones all looking for the same 90VAC at the "proper" Amperage eventually the load becomes so great that no phone rings. It would be like installing 300 Headlights on your car, 2 nice bright lights beats the heck out of 300 "unlightable" bulbs.

 

[mdeeves]

oops thats 24 or 22 G telephone wire

 

[AvayaNovice]

That's why the REN value is there. Too many phones means it won't be able to deliver adequete power.

I'm not really sure what you're asking.

The REN calculation is based off of the amount of amperage the telephone pulls during ringing.

 

[daronwilson]

Keep in mind that older mechanical bell phones required a fair amount of ring current to physically make the bell ring. Many newer phones have electronic ringers, or piezo type elements that draw much less current than the older mechanical bells.

One can either add up the REN as published on the phones, or measure the ring current as phones are added and make sure you don't draw too much.

Good Luck!

It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[cheeses]

If they have 10 telephones and want all to ring, they will need a telephone system. This is becoming more common in large homes. Even if all 10 telephones did ring, could you imagine how loud it would be? Or! 5 is a fair number that will ring if there are no mechanical bells. Turn the ringer off in the other telephones.

 

[Mongo5150]

Yes, it would be loud, IN A 900 square foot house. What about a 2500sq foot house. 4000sq ft? These larger houses are becoming more and more prevelant. Which I agree, at that size you should think about a phone system. They are getting so low in price with online companies selling them now-a-days.

MFurrer@charter.net

 

[crashax]

Honey, did you hear something?
Was that the phone?
Hello?
Hello?