[Asterisk-Users] T1 to T1 on asterisk?

[Mike Ciholas]

On Mon, 25 Aug 2003, Mark Spencer wrote:

> > 1. Will Asterisk route from one T1 to another "perfectly"?  
> > That is, the bits that arrive on the Portmaster would need to
> > be the exact bits sent on the PSTN T1.  Seem obvious that
> > this should be so.
> 
> As of this weekend it does.

Nothing like being on the cutting edge. :-)

What sort of change was required to make this work?

> > 2. Would you predict any trouble interfacing a Portmaster to
> > the Digium card?  Can it both "sink" a T1 (from the PSTN) and
> > "source" a T1 (to the Portmaster)?
> 
> Yes.  This should be fine.  Might consider turning off echo
> cancellation to be sure.

In theory, the modems send the "don't echo cancel" tone to turn 
off echo cancellation in the connection, but I think you are 
suggesting that echo cancellation be manually hard coded off for 
that extension, right?  In that case, is the incoming T1 digital 
stream identical to that handed to the outgoing T1?  Should just 
be a copy inside *, right?

> > 4. Will the above plan actually achieve the "56K" modem
> > connection when routed through the asterisk box?  That is,
> > will there be issues of latency/bandwidth in handling the 64
> > kbps streams?
> 
> In principle it should be able to pass even ISDN calls through.

If that is true, then the bits are not mangled by * at all, 
answering the previous question.  But ISDN is actually *easier* 
in some ways, no DSP on the samples to recover the modulation.

Thanks all for the help!

-- 
Mike Ciholas                            (812) 476-2721 voice
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