Make Free Calls On Your iPhone with Asterisk and Fring

Recently I replaced my Trixbox Asterisk VMWare virtual machine version of my home PBX with PBX in a Flash running on a spare Dell C600 laptop I had collecting dust in a closet. I wanted to get the virtual machine off of my media server which runs Boxee on Ubuntu in order to improve my boxee performance. The day I installed PBX in a Flash, I didn't spend much time configuring it or checking out the cool features as this Asterisk PBX runs all of the phones in the house and I had to keep downtime to a minimum.

I have had several different Asterisk implementations over the 5 years I've been working with it. Currently my system is rather boring. I have a single trunk using a BroadVoice BYOD account and six extensions, all VoIP/SIP devices. The system is configured with a simple IVR with three options. I have a renter in a basement apartment and another person who rents a spare room. Each of them have their own private extension. I then have a ring group set up to handle the main house phones. The IVR allows callers to choose who they are calling and we can all share a single phone number as well as intercom each other.

All of the phones are Grandstream VoIP phones. Most are the BudgeTone 50s and my office phone is a GXP-2000. All of them are set up with a nifty ringtone option which announces the caller id. This is a nice feature because I don't have a cordless phone in my house. So when the phone rings, I can hear who is calling and decide if I want to answer the phone without going to the phone and reading the caller id.

What if I want to answer the phone but I don't want to be tied to the corded phone? Enter the iPhone and Fring.

Anyone who knows me, knows that my iPhone is never more than a few inches away. So with my iPhone, Fring and Asterisk, I now have an instant WiFi SIP phone which makes calls using my home Asterisk system using my Broadvoice account anywhere I have a WiFi connection for my iPhone.

Here is a screenshot of Fring running on my iPhone. Fring on the iPhone

I won't go into all of the details of setting up PBX in a Flash. There are plenty of tutorials online. You can install the free Fring app for your iPhone from the App Store. Here are the steps to get Asterisk and Fring playing happily together...

  • Add an extension to your Asterisk system
  • Set up your router to access your Asterisk system from the Internet
  • Set up a DNS name for your Asterisk system so you can access it from the Internet
  • Set up a SIP (Other) Add-On to your Fring iPhone app
  • If you have gotten PBX in a Flash to work with your VoIP provider and your phone, then setting up an extension for your Fring app should be a breeze. There are no special settings to  get your extension to work with Fring.

    Setting up your router is beyond the scope of this article. But basically you will want to enable port forwarding to your Asterisk server for the FreePBX web interface as well as the phone ports which are typically 5060-5070 and 10000-20000.

    If you don't have a static public IP, I would recommend using a service such as to handle the dynamic IP mapping to your DNS name.

    Finally you are ready to set up Fring on your iPhone. The setup of the Add-on -> SIP -> Other looks like this... Fring SIP Setup You enter the extension you set up earlier in the "User ID" field. You enter the password you assigned to the extension in the "Password" field. And you enter the DNS name for your Asterisk server in the "Proxy" field. Tap on "Login" and Fring will register the extension with your Asterisk server and you're ready to begin making calls and enjoying your new free WiFi SIP phone.