I have a 10/100 4-port VPN Router through which our 4 telephone lines are connected via Cisco 7960 IP phones. Within the last two months all of our calls seem to get garbled. When on the phone, other people can hear us but to us they sound garbled/unintelligible. QoS on the router is set to voice, speedtest of ISP (Natural Wireless) is 10 up/10 down. Trace route between us and our telephony provider, Pingtone, shows speeds consistently under 20 ms along the route, even when calls crap out. Natural Wireless says it's not their problem, so does Pingtone whom we have used for the last 8 years.
Any help, suggestions are appreciated as I'm ready to give up.
