[Asterisk-Users] T1 Hardware Echo Can

[Brent Franks]

Hi Rich,

Thanks for your heads up.  See comments below.

> From: asterisk-users-admin at lists.digium.com [mailto:asterisk-users-
> admin at lists.digium.com] On Behalf Of Rich Adamson
 
> Best think through what you're trying to do here. You have multiple
> choices on how to interface * to the traditional pstn world, including
> the x100p, tdm cards, multiple T1 interface types, external gateways,
> etc.

Currently, I have a T100P card with a T1 crossover cable connected to an
Adtran Total Access 750.  We did have an Adit 600, but had a lot of
problems with it (static, etc) and thought it was the channel bank.
Long story short, ended up not getting along with Carrier Access,
returned it and bought Adtran.  Adtran CS is much friendlier from my
expierences.  So therefore, we are stuck w/ a CB without impedance
matching :(

> The x100p and tdm cards have an internal 2-wire to 4-wire hybrid that
> is built into the chipsets on those cards. In order to use an external
> echo can with them, you'd have to change that to a 4-wire to 4-wire
> arrangement, which cannot be done. The chipsets weren't engineered for
> that.

This shouldn't be an issue here.  Our X100P's on a smaller branch office
do not have that much echo, and we don't hear complaints from these
users.

> If you install a T1 card and an external T1 mux (with fxo cards), the
> echo can function already exists within the mux and/or cards. Don't
> really need 'another' external echo can box unless you actually
> purchased a T1 mux that didn't have echo can in the first place (and
> they do exist).

Our Adtran does not have an echo can built in.  I couldn't find any
Channel Banks that have this feature.  Do you know of any?
 
> If you install a PRI (or related types of channelized T1
arrangements),
> you don't need an external echo can function as those interfaces are
> generally 4-wire to 4-wire interfaces already. If echo exists, its
> generally the result of other interfaces (located somewhere else) and
> those locations should be addressing the corrective actions needed to
> resolve the issue.

I wish we could afford a PRI, however it is really cost prohibitive for
us.

> If you only need a small number of fxo ports, pstn gateways in the
form
> of Cisco boxes, Mediatrix 1204, as well as many other products can do
> that at a relatively inexpensive cost. The echo can function is built
> into those boxes, which do work. Each comes with additional
> considerations or issues however.

The mediatrix boxes do look good.  I'll have to consider for next
project.

Thanks for info!

- Brent