I have spent lots (probably too much) time on dslreports researching (this and other issues). I'll look again now that I have more of an understanding why the calls are being dropped. Vonage has their ACK timeout set at 60 seconds. Here is what one of their evangelists said in response to a similar problem:

The issue is exactly what I described to you in my initial response. On outbound phone calls, when the call is connected at the far end, a SIP 200 OK message is sent to your telephone adapter and this is where the audio stream starts. However, in the SIP protocol this 200 OK requires an ACK to let the far end know you received the 200 OK. Vonage is not receiving this ACK from you but we know your getting the 200 OK since you have 2 way audio when the call starts. Vonage continues to send a 200 OK for 3 retries and is not successful. At the 60 second mark, when the Gateway has not received an ACK from you, the call is disconnected.

As for the inbound calls, I am not seeing an issue however it may still be the same. On an inbound call, the signaling is the opposite. So when you pick up, you send a 200 OK which starts the audio stream and the Gateway send back an ACK which I can see. But, it is possible your device is not getting the ACK which I can't see from the proxy logs. It might not retry the 200 OK messages like the Gateways do.


I have tried several softphones, all have the same problem drop outgoing at 32 seconds (still going thru my actiontec). The Verizon Actiontec has a special version of the firmware that does not provide for bridge mode, so they have dumbed down a questionable product even more. As soon as I have the "backup" box from VZ, I will flash my current one with the non-Verizon firmware - if I brick it, no loss, one has to go back anyway.