[asterisk-users] Outgoing PSTN calls , unusable voice quality

[Veselin Kantsev]

Hello,
I have an Asterisk running with a Sangoma A200 card with Hardware Echo 
cancelling connected to the UK PSTN.
If a PSTN call comes in, voice both ways is OK, however if an outgoing 
call over the PSTN is made I can hear the other party OK but they can 
not, they can barely understand what I am saying, my voice is unclear 
fading and skipping.
Internal SIP and IAX2 calls are OK, incoming/outgoing calls over IAX2 
are OK too. I've tried gsm/ulaw/alaw codecs so far.
Tried disabling the echo cancelling as well.

Any suggestions will be greatly appreciated.


Regards,
Veselin