Problem with transcoding and asterisk 1.4

Hi,

I’ve instalation:
-asterisk 1.4.5
-bunch of SPA-942
-2x SPA-400 as incominng PSTN line
-server 2xXenon

Main codec used by VoIP provider and my SPA-942 is G726-32 and it’s working fine. Unfortunatelly SPA-400 works only with G711A, G711U and G729.
Soo asterisk have to do stream conversion.
When call is established without transcoding G726<->G726 or G711<->G711 sounds great.
But when call is transcoded by server G726<->G711 sound is choopy and very but quality.
To get situation more complicated, setup is:

[general]
disallow=all
allow=g726
allow=ulaw
allow=alaw

[spa400]
disallow=all
allow=ulaw:20
allow=alaw:20
allow=g729:30

sip_peers confinguration in mysql database without “any codec overides”

spa942-spa942 call should be G726 and is working
spa400-spa942 should be ulaw but it’s NOT WORKING and is ulaw-server-G726 (sound chopy)

Asterisk 1.2.19 on the same machine and nearly (1 test peer in file not in database) is working: ulaw-server-G726, sound is good.

Please help me

Best regards

Piotr

No one?

I’ve installed the newest version (1.4.9) and nothing has changed:

Call beetwen ife99-2835

voip-srv*CLI> sip show channels
1.2.19
2835 540e1f714bb 00102/00000 ulaw No Tx: ACK
ife99 cdaeb9a1-c1 00101/00102 g726 No Rx: ACK
sound is clear
asterisk 1.4.9
2835 18dc7a676f7 00102/00000 ulaw No Tx: ACK
212.191.2.20 ife99 e723829a-77 00101/00102 ulaw No Rx: ACK
sound is clear
2835 513a66e06ba 00102/00000 ulaw No Tx: ACK
ife99 cadfb37b-6c 00101/00102 g726 No Rx: ACK
sound is rough

voip-srv:~/asterisk/etc/asterisk# cat /proc/cpuinfo
[4x]
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 15
model name : Intel® Xeon® CPU 5140 @ 2.33GHz
stepping : 6
cpu MHz : 2327.532
cache size : 4096 KB

Please, please, please…

Piotr