Fun and Games with IP Telephony
I’ve recently decided to replace my 2nd telephone line with an IP telephony line from Vonage. There are a couple of really nice features with this service. First of all, the service is really cheap. $24.99/month buys you unlimited local/regional service, and 500 minutes of long distance service. If you go over the 500 minutes, the cost is only 3.9 cents a minute. International calls are also quite reasonable. (5 cents to call Europe, 6 cents/minute to call Tokyo, Sidney, etc.)
Secondly, the service uses a very small box (the Cisco ATA-186) which can fit in my laptop bag; it’s only a little bigger than a portable CD player. So anywhere I have network connectivity, I can have my the telephone line ring me. I’m currently sitting in the Admirals Club Lounge at Logan, and I was able to use the service via T-Mobile wireless access (via my laptop which acted as a NAT proxy). I can also set up the service such that if my ATA-186 isn’t on the network, the system will automatically forward my call to my cell phone.
There are other nice features as well, such as two Vonage customer can basically chat with each other indefinitely for free, and being able to set up a secondary phone number in some other part of the country so that friends/family in that part of the U.S. can call your phone using a local number.
There are some downsides. Currently, the talk path is *not* encrypted so someone who is sitting on the network path between you and Vonage, and who knows how the reconstruct SIP packets, and very easily tap all your phone conversations. On the other hand, it’s not that much harder to tap physical analog lines as well. The place where it’s really problematic is when you’re plugged into a blatantly insecure network, such as a conference/show network. On the other hand, IPSEC to a less publicaly accessible subnet will do much to mitigate this risk. (Next on my to do list — to set this up). Also, the unit also requires a transformer which is a pain to pack. Fortunately the unit seems to use only “+5V, so I’m thinking I might be able to power the unit from the laptop’s USB port.