How to get Cheap calling on your iPhone

VoIP calling is becoming more commonplace, and your iPhone is one of the easiest ways to try the service out. There are many softfone applications available for the iPhone. There is also a multitude of VoIP providers touting for business. My experience with it is by no means comprehensive but its great to be able to introduce the technology to others.

What is VoIP?
Stands for Voice over Internet Protocol. Basically your speech is digitised and sent as packets over the Internet then replayed as audio to the recipient. There are several ways of doing this, and the iPhone is possibly the easiest platform to achieve it. Skype is a wellknown provider of VoIP, it however uses a proprietary client and undisclosed codecs. FaceTime operates on similar principles to Skype. These operate peer to peer, each user has to be either: logged in; or in the case of FaceTime, in the right environment (in wifi enabled broadband range). Skype does offer calling to the pstn telephone network, this was originally known as SkypeOut. Purchase of prepaid credits or a subscription is required to call telephones. I'm primarily focussing on VoIP providers that utilise the non proprietary SIP standards and connect to the telephone network as a workaround to expensive circuit switched voice calling.

How much does it cost?
Casual calling rates are typically around 2-5 cents per minute to landlines locally and internationally
Mobile rates are in the order of 20-50 cents per minute. Most VoIP providers have free minutes with a subscription, some provide free minutes without any monthly fee.

Where do I get this cheap calling?
There are untold VoIP providers. I have selected a couple to try and my findings are outlined in this post.
2talk: this is a NZ based provider that offers a variety of plans. I have used the go free plan which offers 15 minutes of free calling to NZ landlines a month, 3.5 cents overage, and 22 cents to mobiles.
VoipCheap: A European company that offer free calling to selected countries (up to 300 minutes per week) provided you buy some credit every three months. Overage to NZ landlines is about 2 cents per minute and mobile calling is 17 cents per minute.

Is there an app for this?
Yes! They are known as a softphone or a SIP dialler.
You can download the 2talk app; be warned that the account type available signing up through the app does not include any free minutes per month. From my experience it is better to signup online on the 2talk webpage then enter your details into the settings pane within the 2talk app. It is possible to easily add credit using a credit card through the app. The 2talk iphone app is unfortunately low tech and does not support iOS 4 task switching or voice backgrounding or low-bitrate codecs.
There is an App called Mobilevoip which is aligned with the Voipcheap provider. Signup etc is available through the app.
These apps provide basic functionality, for advanced users there are superior softfones which offer Bluetooth support, favourite contacts, alternate codec support, call recording, automatic speaker phone, SMS etc.
I have tried the Acrobits Softfone which has proved a very stable fully featured application. It has a wizard to set up a variety of SIP accounts including Voipcheap. 2talk had to be configured manually on Acrobits Softfone. A search in the app store for voip will bring up a selection of softfones. I purchased Acrobits based on its functionality and its pricing of the G729a licence (available as in app purchase) The other commonly recommended app is called Bria.

How much data does it use?
The higher quality codecs use more data, however depending on your bandwidth this can lead to issues with dropouts if a codec with high quality is used. G711 is a codec that uses 64kbps. This typically is fine over a good broadband connection. If you are wanting to call over a 3G connection then it us advised to use the G729 codec which consumes 8kbps but maintains a reasonable voice quality. So how much data will it use in practice? I find allowing for 1 MB every 4 minutes is about right on the G729 codec. You need to factor in your data cost to work out your real calling rate, which will vary hugely depending on your carrier and data plan. Note that you need to go into settings online via the 2talk live portal (or Voipcheap settings online) and enable whichever codecs you require, then match the codecs in the Softfone settings, in the desired priority order.

What are the cons?
If you've used skype then you'd understand what a bad connection will produce, voice dropouts and chopping. This seems to be prevalent in poor upload conditions. From my experience on my 3GS this is a limitation. I am on Telecom XT which helps 3G coverage, but the lack of HSUPA is evident. The iPhone 4 should give more stable performance as it supports HSUPA upload speeds on all New Zealand network frequencies. I have experimented using a MIFI device on Vodafone supporting HSUPA and results are more favourable; i.e. less call drops or chopping in voice. Using a wifi connection to an adsl broadband connection is generally faultless in performance, and advanced users can implant QoS settings to assure the performance. I have noticed that using 2talk has less latency in voice transmission than Voipcheap, this potentially because local servers reducing data transmission distances I guess. If using mobile data while on the move I suspect that there will be dropped calls. I have used this for short calls while on a moving vehicle, but have no confidence that cell-handover will occur in a timely seamless manner like it does for normal circuit-switched voice calls.

Where can I find out more?
I just found this excellent article by Steve Biddle. I will link to it because it is very relevant: http://www.geekzone.co.nz/sbiddle/6421

One day I might write a post on how to send faxes from your iPhone using 2talk. Stay tuned.