[Asterisk-Users] T-1 vs channelised T-1?

[Michael Graves]

On Tue, 21 Dec 2004 23:21:50 -0800, Chris Travers wrote:
>Fractional T1's don't have the 4 to 2 wire conversions at your phone 
>switch of you are doing VOIP or other digital telephony technologies.  
>As a result, you should not have to deal with echo cancellation as much 
>if you are on a fully digital circuit.  This means your system is 
>simpler and easier to maintain if everything is digital end-to-end.
>
>However, T1 cards are far more expensive for a few lines than FXO cards 
>so if you only need two lines, you might consider a BRI instead, and 
>maybe POTS with DSL.
>
>Fractional T1's are just an ordinary T1 with only a certain number of 
>channels active.  You still have all the hardware needed for a T1, but 
>you are not paying for more capacity than you need on the actial telco 
>connection.
>
>For 4 or fewer lines, I would probably consider dual BRI's or quad FXO's 
>(due to infrastructure cost) but for more than that, I think that the T1 
>solution is so much easier to work with that it wins out completely.  Of 
>course if you need to be able to add capacity quickly, then the 
>fractional T1 is better.

The problem is the FXOs. As has been mentioned on list many, many
times, FXO interfaces generally suck. I presently use a TDM400p and
it's the best I've tried thus far. If it doesn't end up satisfactory as
I scale to 3 or 4 lines then my next move will be to try BRIs.

FWIW, I'm also going to try adding a Zultys 4x5 IP phone. It has one
on-board FXO which was initially only for life-line use. However, their
most recent firmware allows the phone to forward the FXO to the pbx for
voicemail, forwarding, conferencing, etc. I don't think that the pbx
can make a call through the FXO, but the phones internal dialplan can
select the FXO for certain calling patterns, ip for all else. A friend
has this phone and is not using it at the moment. I'm going to borrow
it for a month and see how it does. It also has bluetooth for headset
applications. Maybe very nice.

Michael

--
Michael Graves                           mgraves at pixelpower.com
Sr. Product Specialist                          www.pixelpower.com
Pixel Power Inc.                                 mgraves at mstvp.com

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