[Asterisk-Users] Digium TE405P and Cirpack Switch

[thieumS]

Hi,
    I've got an * box with 4 E1 (TE405P) and a Class 4 Cirpack switch 
(www.cirpack.com).

<IP Network>--<*>--<Cirpack>--<Public PSTN Network>

ISDN interco is EuroIsdn, ports are configured ccs, hdb3, crc4. Cirpack 
is Network, * is Terminal/User.

As I encountered some pb with Sip to Zap transcoding (* to Cirpack way 
poor quality, the other way fine), I tryed to put a loop on * in order 
to make a 100 % TDM call and qualify only the ISDN side.

in zapata.conf, echocancel is on, echocancelwhenbridge is off.

A=calling one
B=called one
both are PSTN terminals

1) Incoming call on my Cirpack from PSTN.
2) Routing to *
3) On *, routing back to Cirpack.
4) On Cirpack, routing to PSTN.

=> Quality B to A is perfect.
Quality A to B is very poor, crackling sound, a strong crackling echo.

I am observing the same effect when performing a Sip-to-Zap call. That's 
a one way problem.

If you have any idea, or tweak settings which could help, you're welcome.

thieumS
* 1.0.5
zaptel 1.0.4