Anybody use a wi-fi/GSM phone? (UMA/GSM)?
 

[I thought I posted this yesterday, but can't find it.]

T-Mobile began selling UMA/GSM service. It let's you make unlimited calls within the U.S. when connected via wi-fi.

Reason it is pertinent here is that many claim, including tech reviewers, that when overseas and using the phone via wi-fi, it is billed as though you are in the U.S. This means all incoming and calls to U.S. would be "free".

No one has posted first hand that this is really how billing will work. I have used this service and handoffs between wifi and GSM are seamless. It is clearly stated that there are no handoffs if you are in a roaming area.

I believe this type of service has been in Europe for several months. Can any one comment about it and how it works for them when traveling?

...mike

I have a WiFi/UMTS handset (E65 by Nokia) and my experience with "free incoming calls" is thanks to Fring (fring.com). My operator doesn't have any offer similar to T-Mobo but thanks to Voip and 3G/Wifi connection I'm using a local italian number (Eutelia, SIP connection) in Italy and abroad. This is great because I have a landline number everywhere but attention. Wifi connection by mobile phone is "freezing" very often (more than usually) and not everywhere I have a free access... so when I can use a 3G offer is better (except some delay :D )

If I understand you properly, you are saying that you experience pauses or drop-outs in the VOIP conversation when connecting via WiFi. Do you think this might be due to heavy loading on the underlying Internet connection (e.g. DSL) or is it something about WiFi?

I recently upgraded my cellular data plan and would be interested in knowing if VOIP over EDGE is even possible. I understand that the latency can be a problem.

Don. Privately IM me with what continent you are on. I am in North America until the end of November. I have access to HSPA and EDGE. I'd be happy to play around with you on this.

I have the Blackberry 8320 with UMA. It is AWESOME! I have used the UMA in Japan, Germany, and Switzerland this month, and, yes, using UMA anywhere is "free," as you state. Technically, it is unlimited for calls to the US if you subscribe to the @home service (which was $9.99 when I did it, now is $19.99), and if you aren't subscribed, voice usage just deducts minutes from your plan, as if you were in the US.

I have even done a "pay for the day thru web" access for Wifi in Germany from (via T-Mobile Hotspot) with my 8320, and UMA then also works.

I use the Linksys travel router when I am on wired internet in a hotel room - works flawlessly. The Apple Airport Express does NOT work with the voice portion of UMA - the Linksys does.

DLink's travel router works with UMA as well. On any travel enable IPsec VPNs. It helps.

DR, I tried voip over EDGE off my laptop while stationary and it was tolerable. I tried it off a PDA and it sucked. Draw whatever conclusions yhou want.

I also made a quick unscientific test using VoiceStick VOIP over my GC83 card with T-Mobile's VPN data service. The results were interesting but not vey useful. Very long delays, a lot of echo, pauses, etc.

My experiments were about the same. Over HSDPA, the quality was ok. Over EDGE it was two way radio quality at best. Perhaps if you put a beep in it and treated it as push to talk or something.

Update: I just tried Fring on my E61 (on EDGE) and the connection quality was acceptable. Not great, but workable.

My E61 works fairly well over EDGE (on Cingular) using iLBC as the codec. I wouldn't bother with g729 as Nokia's implementation is terrible.

Most VISPs don't support iLBC but you can always use Asterisk as a transcoding proxy.

Vlad,
This is very interesting but could you explain what iLBC and Asterisk are?