It allows you to call in to your Asterisk server, get a dial tone, and then dial back out as if you were using a normal extension on your system. I use this lots to make cheap international calls from my mobile phone.
You may also wish to route your DISA calls via A2Billing. If you’ve integrated FreePBX and A2Billing as described here it’s a simple case of changing one setting on your DISA setup in FreePBX.
One of the great things about voip is that you can make international calls at local rates. Combine that with Asterisk/FreePBX and you’ve got the ability to make cheap international phone calls using your mobile phone.
To do this we’re going to setup DISA (Direct Inward System Access). This will enable us to ring our Asterisk server, get a dial tone and then dial back out again.
Then I will show you how you can combine this with callbacks if that works out cheaper for you.
Installing the modules
First we need to install the DISA (if it’s not installed already) and Callback modules. See part 5 for more information about installing FreePBX modules.