[asterisk-users] PRI Card

[mail-lists]

Jared Smith wrote:
> On Thu, 2007-07-19 at 12:11 -0400, mail-lists wrote:
>> thanks for your reply - Our setup isn't complicated at all - just a PRI 
>> coming into an asterisk box. Maybe you could answer another question for 
>> me - what disadvantages does a PRI have from a channelized T1? or vice 
>> versa.
> 
> A channelized T1 is 24 channels over a T1 -- basically little more than
> 24 POTS lines that happen to come across a 2-pair digital interface
> rather than 24 pair analog interface.  PRI over T1, on the other hand,
> only gives you 23 voice channels (often call B or Bearer channels), and
> uses the 24th channel for call signalling between you and the upstream
> switch.  (This channel is called a D or Delta channel and I've even
> heard it called a Data channel, although my friends in big telco say
> that the D doesn't stand for Data.)  PRI gives you much more advanced
> call control, allows you to more easily do things like DIDs, and gives
> much quicker call setup and dialing.  Depending on your location, the
> only major downside to PRI might be price... they're often more
> expensive than channelized T1s.

That's what I pretty much thought - We're about to sign a two year 
agreement so I wanted to make double sure a PRI was the best route.

> 
>> is the TE205 the double port version of the TE120P?
> 
> Yes, the TE205P is the 2-port version of the TE120P.  Once you get to
> the 2-port versions and 4-port versions of the Digium cards, they come
> in three flavors: a card for 5-volt PCI slots (the TE205P, for example),
> a card for 3.3-volt PCI slots (the TE210P, for example), and a card for
> a PCI-Express slot (the TE220P).
> 
>> Also, what's required as far as echo cancellation goes? Is that built 
>> into these cards or do you have to move up to a TE207P?
> 
> It depends... if you're OK with software echo cancellation, you don't
> need anything special.  If you want the hardware echo cancellation
> (which many people do), you could move to the TE207P or TE212P cards
> (for PCI slots in 5v and 3.3v, respectively), or the TE220P plus a
> VPMOCT064 echo cancellation module.

I'm going to look into what sort of overhead software echo canceling 
incurs and go from there.

Is it possible to get a TE205 and then add the echo cancellation 
separately  or are they sold as a unit?

I don't see any info about the TE220 and a google search for vpmocto64 
didn't turn up much.


> 
>> What is the difference between a TE205 and a TE210?
> 
> Explained above... difference between the different types of PCI slots.
> 
>> Sorry about all the qeustions - the info on digiums web site doesn't 
>> really make this clear.
> 
> I agree. Luckily, I know Digium's marketing department is working to
> improve the information on the website so that it's clearer which
> hardware is appropriate for different situations.
> 
Thanks for all the advice/answers.