[Asterisk-Users] Voice quality problem from calls from * to * thru IPtel SER server.

[Kong]

I have 2 * server, each connects to a IPtel SER server.

i have another ATA which also connects to IPtel SER server.

when * call * thru IPtel server, i have jitter and voice quality problem, 
but when i use the ATA to call both * server, there is no problem, the 
quality is superb. the same thing happens when i use * to call back to ATA.

So, i was wondering what did i do wrong?

please help me..

[general]
canreinvte=no
nat=no
dtmfmode=rfc2833
Autocreatepeer=yes
port = 5060
bindaddr = 0.0.0.0
maxexpirey=1800
defaultexpirey=300
rtptimeout=60
relaxdtmf=yes
rtpholdtimeout=300
tos=0x18
disallow=all
allow=ulaw
;allow=alaw
allow=gsm
allow=ilbc
context = from-sip-external
callerid = Unknown

register => XXXXX:XXXXXX at XXXX.XXXXXX.com