i have tested four ip phones in the LAN namely soundpoint 501, GXP2000,budget tone 200 and from atcom(i guess atcom 100 something) and also PSTN phone
when i make a call from PSTN to any ip phone and vice versa i experience a little echo
too bad for ears to listen. but when a call is made thru ip phone to iphone everything is fine,
what would be the remedy on this?
i remember about RX gain and TX gain in zaptel.conf where someone told me this is responsible for the echo with PSTN phone
Any idea please