Blocked SIP ports

[shashi]

Hi !

I am using a Linksys SPA-3102 at my office in India to try and make calls to another SPA-3102 which is working properly in my US office.

Our ISP in India has blocked the SIP ports and hence my ATA could not register with Gizmo.

I tried to configure my ATA with Voxalot using port 443 to bypass the SIP-port-block, but I am unable to call the echo line at *600. I get a fast-busy tone after a few seconds when I dial *600. I have programmed the ATA asa per the FAQ given on the Voxalot website. My ATA gives me a dial tone but unable to call any numbers.

I even had someone call a SIP-Broker PSTN number in the US and then dial *010 and my voxalot number but this call does not come through either.

My ATA in the US office is working on Gizmo but I can easily change it to using Voxalot.

What else do I need to check on my ATA's programming ?

Thanks for the help !