[asterisk-users] SPA3k wired to PAP2 for echo testing

[James Harper]

In my seemingly endless search for the cause of echo on my SPA3000, I
wired it up in the following configuration:

Analogue Handset <--> (FXS)SPA3000(FXO) <--> PAP2

And set the Line1 dialplan on the SPA3k to '(<:@gw0>S0)' which means
that as soon as I pick up the handset I get linked straight through to
the PAP2, which gives me dialtone.

Even in this configuration, with my impedance settings set to the
Australian standard of 220+820||120nf, and the PSTN and PAP2 echo
cancellers enabled (or not, and all combinations of) I get local echo as
soon as I pick up the handset (I hear my voice bounced back to me).
Surely this shouldn't be??? There is no hybrid involved at all!

If anyone on this list with a SPA3k (that doesn't have any local echo
problems on the PSTN port) and an ATA with a FXS port, could they please
try the above setup and post the results (including SPA3k hardware and
firmware versions, and the ATA used)? I wonder if there is a problem
with some versions of the SPA3k where there is some sort of inbalance on
the PSTN port that causes echo right there rather than further down the
line?

Thanks

James