For quite some time now I’ve been on the hunt for a decent SIP client for the iPhone. At one point I almost gave up completely as it seemed that the only people that were interested in releasing SIP clients for the iPhone were companies that provided a “pay for” SIP service. There was no generic SIP client that actually delivered acceptable voice quality.

I know there are some great applications if you have a jailbroken iPhone, but I was looking for something mainstream, especially if I was going to evangelise the solution to less technical colleagues and customers.

Having access to a corporate SIP service at the office I was keen to find something that worked really well, primarily because everyone that had a Nokia device running Symbian could make VoIP calls and I couldn’t.

There are now finally a handful of decent clients available in the App Store that do almost everything that I needed them to do:

– ability to use my own SIP server configuration.
– ability to use the built in address book.
– support for the G.729 codec.
– ability to make GSM calls from within the application.

Ideally, I’d also like the application to be free, but so far this hasn’t happened. All three of the applications that I feel are worth considering carry a £3.99 price tag from the UK iTunes store (click here for instructions on how to create a UK iTunes account without a UK credit card).

The only feature that all of the applications fall short on, is the G.729 codec support. With bandwidth constraints in South Africa G.729 compression for voice over IP has become commonplace.

After reading a few reviews and comparing feature lists I eventually settled for iSip, knowing that the lack of G.729 support would mean that I would be restricted in the destinations I would be able to call. After the initial configuration (which was incredibly simple) I was happily making calls to certain destinations. The call quality was excellent and connection time was extremely quick. The ability to have multiple profiles meant that depending on whether my iPhone was connected to the corporate VoIP network or a general Internet WiFi hotspot I was still able make calls without having to change settings.

I have put in a feature request in with the application developer, but as yet I have not received any feedback as to if or when this is a possibility. I know there are some licensing issues when making use of G.729, but I’m pretty sure they could just work that cost into the price of the application.

Below is a list of the applications that you should consider if you are looking for a Generic SIP client sans G.729 support:

isip.png WeePhone.png Acrobits.png
iSip
WeePhone SIP
Acrobits Softphone

I thought I would also make mention of Nimbuzz and Fring. These two applications are free in the App Store and they allow for custom SIP settings, but both require an active connection to their respective servers to “log in” and actually make calls. This results in a terrible speech delay and I’ve found them to be almost unusable. Others may have better luck. Also,most corporate VoIP networks probably won’t allow connections to the Internet, which renders the applications completely useless.

Nimbuzz.png Fring.jpg
Nimbuzz
Fring

The quest continues…

Update: I received a response from the developers saying that they are in negotiations with the G.729 license holder and that they aren’t able to include support for the codec until they have concluded the discussions.