In general, RingFree will work with any Voice over IP Service Provider using the Session Initiated Protocol (SIP) in a standard manner. Besides that, the service provider must :

• Share your user credentials (user name and password) with you;
• Allow you to make telephone calls without being "registered" with the service. 

Let's look at these separately.

Credentials

Many VoIP service providers (Vonage, and others) provide unlimited calling plans but do not share with you the credentials necessary to make calls from devices other than the locked device they provide. In many ways, these VoIP operators are not much different than the old US telephone companies who sold you a service, sold you a phone, and forced you to only make calls on their service on that particular phone. Vonage and other such companies are now in deep financial trouble (do you think there's a relationship between their difficulties and the fact that they operate like the telephone monopolies of the 1950s? We do.) 

Anyway, a lot of these unlimited outgoing call companies want to limit the calls you make at any cost. One method they use is the locked telephone device: you can use that device to make a call, but no other. Obviously, you won't be able to use such calling services with RingFree.

Non-registered Calling

Typically, a VoIP service provider allows you to "register" a hardware device (such as an analog telephone adaptor, an IP phone, or a PBX) with their service. The hardware device is set up with the information needed for service registration (a proxy address, your user name and your password, at a minimum). The device then contacts the service at the proxy address and reports in with your user name and password, and the current IP address of the hardware device you are registering. Now, the device and the service know where each other is and can talk to one another. When an outside party calls you, the service provider then knows what device to route the call to.

RingFree does not offer incoming call services (at least not yet). So neither the dialer nor the RingFree server "registers" with a service provider that you enter. Fortunately, most (but not all) service providers allow you to make a call without being registered.  The way this works is that a device contacts the service provider, telling it it wants to make a call to a certain number, and also sends along the user name, password and IP address as part of the request. The service then checks to see if the user name and password are legitimate before proceeding with the call.

When you store your service provider information on the RingFree server, you are essentially  setting up RingFree's server as a hardware intermediary between your iPhone and your VoIP service provider. 

ge ( These lists are not even close to being complete, but over time we'll keep updating them. Please let us know of your experiences.

Let's start with the bad news:

Providers/Services you CANNOT use with RingFree

• Broadvoice: Sadly, one of our favorite VoIP providers, and one of the few to offer unlimited calling and are willing to share credentials with their users, does not work because the company does not allow calls without device registration. We've let them know and hope their history of innovation in the industry will prevail.
• Packet8: This company offers a lot of innovative plans. Unfortunately, they limit their customers to the generally very cheap calling devices they sell and refuse to share user credentials so their customers can upgrade to better hardware as well as use services such as RingFree.

Providers/Services you CAN use with RingFree (fully tested)

• Gizmo Project: No limits.
• PhoneGnome: No limits.
• Race Technology: No limits.
• VoicePulse: VoicePulse Access and VoicePulse Connect plans work well with RingFree. The company does not share credentials on its unlimited calling plans.  
• Vonage: Only their "soft-phone" product, for which they charge $5 month in addition to their standard monthly service fees.
• Voxalot: No limits.

 These are RingFree's Preferred Providers. They have undergone rigorous testing on our servers and we have added much of the configuration information for Preferred Providers right into our back end databases, greatly simplifying their set-ups. Preferred Providers pay RingFree nominal testing and monthly fees to be listed on the dialer.

If your provider does not appear as a Preferred Provider, you will need to select "Add Your Own" from the pulldown menu and enter the configuration information manually.

 Your service provider must give you the following information:

• The proxy address for their SIP server;
• Your user name for the service;
• Your password for the service.

Without all of the above, you will not be able to access your service provider through RingFree. Please contact your provider directly for the information you need. Some are willing to share it, others not. If they don't, you may want to take that into consideration when determining how much they want you as a customer. 

That depends on whether you currently make international phone calls on your cell phone. If you do, expect to save bundles. If you don't, your savings won't be as substantial, but if you sign up with a service provider and buy some calling minutes, yoy may make inrernational calls you would never have considered placing on your cell phone.

Let's do some comparisons to help you decide.

Let's assume you would make about 2 hours of international phone calls a month, with all calls to European locations.

If you're an AT&T customer, at these calling patterns you make enough overseas calls on your cell phone that it's a no-brainer to sing up for AT&T World Connect at $3.99 a month (without World Connect, your international calls on your iPhone would run about $3,300 a year).

On AT&T World Connect, the typical per minute charge of calls to Europe is US$0.09 per minute. So at two hours of such calls per month, you would be paying AT&T about $178 for the year (two hours of calls a month at 9 US cents, plus the $3.99 service plan).

Its easy to find rates at about 2 US cents a minute for calls to Europe (even less by shopping around). At your calling patterns, your calls over RingFree to Europe for the year would run you about US$29.00, or about $16 percent of what you pay AT&T.

RingFree is not in the business of selling calling plans. But there are plenty of reputable VoIP companies that do. And if you're worried about the wuality of a VoIP international call versus and AT&T international call, you shouldn't be -- even AT&T now uses VoIP for virtually all international calls.