voip over wifi via cell phone

[Michael Torrie]

On 02/15/2011 11:20 AM, Jared Smith wrote:
> On Tue, Feb 15, 2011 at 12:27 PM, Jeff Moyes
> <ml at mindstormdevelopment.com> wrote:
>> I've heard that with smart phones, if you are in a wifi zone that you
>> can connect to, you can reroute your calls over the wifi (using voip)
>> and not use the cell radio (and therefore not use up cell minutes).
>
> That's correct.  I've been doing it for five or six years now.

I think that only T-Mobile has phones that can tunnel GSM over 802.11.
And they are not necessarily even smart phones.

If you're referring to SIP, I also use it.  Well I have used Google
Voice and gizmo on my phone for quite a while.

> Support obviously varies from smartphone to smartphone.  Many of the
> newer Nokia smartphones (most of the E and N series) have a SIP client
> built into the OS, which makes it much better on the battery life, as
> the OS handles the wakeups appropriately.  Things seem to work OK for
> me on my Android devices, but VoIP calls really tend to chew through
> the battery pretty quickly.

My Nokia E65 chews up the battery when any 802.11 is on.  Even without
taking calls, I get maybe 40 minutes.  The 802.11 radio really sucks the
juice (probably because it's very chatty compared to the cell radio).
iPhones have a bigger battery, but 802.11 still cuts into battery life.

>> In addition to any help from the list, does anybody know any good
>> resources that talk about this (hopefully without tons of telecomm
>> jargon or else explanations of the jargon as you go)?
> 
> Not off the top of my head -- but feel free to ask on the list here,
> and I'll try to respond.

We used to have a Asterisk users group in Utah, but from the google
group, it's been dead a long time, sadly.