[asterisk-users] Re: can Digium FXS channels support been half mileto 1 mile length away from phone?

[Steven]

You want to look up REN or Ringer equivalence number .

The old PSTN phone that had a mechanical bell required a certain wattage to run the motor.
That was later called 1 REN.
It is a measure of the electrical draw from the device when ringing.

The ringing is triggered by a voltage spike, but the wattage draw is what he is referring to.
Think of plugging in too many microwaves and blowing a fuse.

Most newer phones, because they a speakers instead of motors, have a REN of .5 or lower.
Most cordless phones are more like .1 because they use wall power for the ringer.

I have not noticed it on Digium equipment, but most devices have a REN number on them. (or in the specs.)

I used to use an old USR ISDN terminal for my inside analog lines.
It had a REN of 4, so I could plug in 4 old "Bell" phones or 8 .5 REN phones, etc.

If you exceed the REN, sometimes not all of your phones will ring, sometimes none will ring or worst case, you will damage you 
equipment.

Wattage is lost over distance, so after that half mile, the REN will be some factor lower than the spec.

You said that you do not expect them all to ring at once, so I assume that you are running 6 separate lines that distance and only 
plugging one phone into each one.
I wouldn't expect a problem in this case.



-- 
-- 
Steven

http://www.glimasoutheast.org



"Manrique Feoli" <manrique.feoli at kinetos.com> wrote in message news:44DA4E98.5090505 at kinetos.com...

Thanks Rich,

I was expecting that.  I was worried because on other type of cards if
you set the phone too far you'll burn the port of the card, mainly
because of the lack of capacity to keep such a long line up.

Now when you say 2 or three ringers,  you mean 2 or three ring events or
phones ringing at once  or what did you mean?   I need 6 phones now,
and not expecting more than 2 ringing at once.  (hopefully)

cheers
Manrique



Rich Adamson escribió:
> Manrique Feoli wrote:
>> Hi all,
>>
>> I need to setup 6 phones about 3/4 of a mile from the main box,   (can't do it with VoIP yet because of networking issues),  does 
>> anyone knows if the boards can resist such a length for FXS ports.  Right now there is a Dialogic MSI160 working fine.
>>
>> The actual length in a straight line is about half a mile,  it does have a single cable point to point, but can't be sure where 
>> the cable goes since it has to pass from one building to another,   so it might end up been quite a bit more distance.
>>
>> If the answer is they can't handle such a distance does anyone knows  if there is an alternative,  (line booster or whatever 
>> similar )
>
> With the exception of the ring generator on the digium card, the fxs port specs are basically the same as telephone company specs. 
> Telco lines in rural areas often times exceed six miles. So, yes the digium card will handle your half mile just fine.
>
> The ring generator on the card is much smaller then those used in the telco, and is likely limited to maybe two or three ringers 
> at the distant location. Don't plan on attaching multiple phones to the fxs port at your remote location. (Same is basically true 
> with the sangoma card.)
>
>
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