I have some problem maybe some of you guys can help me with.

 

I have  ATA device connected to hub -> router -> ser server (5060) -> asterisk (5061) -> pstn

 

sometimes when i am making a call the other side can not hear me, but i can hear the other side, it happens sometimes, and sometimes it's working fine.

 

where i can start to check the problem in order to solve it.

 

thanks for any help.