Technology & Gadgets

SIP Voice over IP

So, after nearly 3 years with Vonage VOIP , I’ve made the switch to a SIP provider. For those who do not know, SIP is Session Initiation Protocol , an open standard for internet telephony. Many folks know SIP from an article in Wired about Gizmo , a SIP client for the computer.


I chose InPhonex as my SIP provider, and bought an unlocked Linksys RT31P2-NA from them (locked means it can only be used with one SIP provider, or more commonly VONAGE).


Why InPhonex?


  1. They had 303 area code numbers available (it’s a prestige thing, but nobody likes the 720 area code numbers)
  2. They seemed well-rated
  3. They had a pay-as-you-go and DID (direct inward dial) plans that could be combined.

So what’s the difference? Almost none, except I’m paying $7.95 per month for DID unlimited minutes, and $0.025/minute outward dialling rates, compared to Vonage’s $14.95 basic plan with 500 free minutes (in or out).

So this covers landlines. For computer phones, I use X-lite , an amazing free client that works entirely well.


My Qwest DSL service is still incredibly unreliable, so I lose calls/internet radio when that goes down. The other cool thing is that now that I have an account with a SIP provider, I could set up that Asterisk PBX I’ve always wanted…


So far, service with InPhonex is OK, their support is unhelpful (require advanced degrees to setup VOIP router). Their ordering system is attrocious, but as long as service is OK, I’m OK. The Qwest DSL/SIP interaction is problematic, as I’m not sure the SIP always “dials back out” when Qwest reestablishes itself.

By Dave

He was born in Canada, but currently lives in Boulder, CO up in Boulder Heights.

2 replies on “SIP Voice over IP”

Well…. It’s now September 10th. I gave up on SIP and InPhonex August 10th. I’m not intending to renew.

Here’s my thinking:

  1. Despite having received a personal e-mail from the president of InPhonex (after my post above), they are unable to provide any reasonable solutions to the reliability of callback when internet goes down using the same exact router that Vonage is able to deal with easily.
  2. With my new E61 phone from Nokia, I am easily able to do SIP from the phone. Contrary to their public statement, Gizmo and SIPphone are able to offer (303) area code numbers, and a very competitive price vs. InPhonex ($35 per year vs. $8 per month). My new number is too cool to post.
  3. I think I recently got to the bottom of my Qwest DSL problems, and am thinking of giving SIPphone another chance to beat VONAGE (my Linksys router can talk to any SIP provider).

So, in summary, SIP still rocks, but InPhonex doesn’t.

I also found out from a friend a couple of factoids that I should have known:

  • Vonage uses SIP under the hood, it’s just hidden
  • SIP can’t traverse NATs/firewalls well, the IASP (sp?) protocol from Asterisk can, which is why I should be using that (just need an Asterisk server soon)
  • Skype solves the NAT traversal problem with peer-to-peer phone sharing.

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