Using an Iphone 3G with Asterisk and SIP

I’ve been testing an application called SipPhone for the Iphone (

It works over WiFi only (obviously, as the mobile providers don’t want you using VOIP rather than paying for their minutes!) and it works pretty well. It was easy to get it registered as an extension on my Asterisk server and start making calls as you would with any other SIP or softphone.

The quality was very good although it will obviously depend on how good your Wifi connection is. I had some trouble getting it to stay registered with my Asterisk server although that will be to do with my setup. My Asterisk server is on a public IP address and my Iphone was on my home WiFi connection, which is behind a NAT router.

I probably could have got it to stay registered by playing around with port forwarding on the router but is wasn’t really worth it due to a bigger problem. Apple do not currently allow 3rd party apps to run in the background on the Iphone. That means as soon as you come out of the SipPhone application it’s no longer running, so you’re no longer connected anyway.

So while it’s great for firing up and making outgoing calls it’s probably not practical for incoming calls. This may change in the future if Apple allow applications to run in the background.

5 thoughts on “Using an Iphone 3G with Asterisk and SIP

  1. John

    I installed the Acrobits Softphone as an extension on my Elastix pbx It works well over wifi, and the setup was straightforward.
    This app is 3g capable, although I didn’t try it as I couldn’t get any type of vpn working from the iPhone over 3g, (local carrier problems) and I wouldn’t consider any other type of remote connection.

    As mentioned, the application will shut down when you close it – unless you use the Backgrounder app with a Jailbroken iPhone. But there is a downside to this – it eats the battery. All in all I find that voip over wifi is a bit hit-and-miss at the best of times.
    Finally, I find this blog helpful and informative, please keep up the good work.

  2. matt Post author

    Thanks for the useful info. I’ve found VOIP over WiFi hit and miss too, although sometimes it can work well.

    I’m glad you find the blog interesting, and thanks for taking the time to post.


  3. jeremy Viccari

    I find that wifi is very clear, running FreePBX Asterisk 11 on CentOS 6.4. I am using a SIP client on my iPhone, initially I used one called JOIN, but I had problems with multiple accounts with that application.

    Then I found Groundwire from Acrobits. They have a Keep awake setting for when I am on wifi, I do not lose SIP registration and therefore have no problem getting incoming calls. I can have the APP not in the foreground and still get incoming.

    I have documented the settings for groundwire to work on iphone 5 on wifi, but now, I want to get it to work on 3G.

    iPhone 5 is on 6.1.4, as the app did not work on ios7 beta 2. I had to roll back to ios 6.1.4 to get the app to work.

    That is where I am at so far.

    I have 3 google voice lines running on the asterisk server and the sip client connects to them all.

    Once I have the settings for 3G/4G, and wireless that is not on my home LAN, I will be all set.


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