Start by downloading the application from the Google store with following this link:
Click on Application to buy and download.
Choose option -> Use Push notifications
To add a new Sip account choose -> New SIP Account
Fill in your account details and click -> OK
Title = Your phone number in format 41xxxxxxxxx
Now it’s time to configure advanced settings of your account.
Go to -> Advanced settings
Set the Codec preferences for WiFi and 3G in order shown below.
To change them just drag-and-drop the codecs by tapping the square icons available on right corner of each codec (shown on screen shot).
Important note: codec G729 must be bought separately.
Below you will see how to buy the mentioned codec.
Please note also that in Groundwire you can install few SIP accounts and for each SIP account the codec G729 must be bought separately, as well as the WiFi and 3G codec preferences must be set up, again separately for each account.
To buy the codec G729, go to Groundwire Settings.
Another important point to check is to make sure if for incoming calls you have option -> Use Push Notifications.
If not, choose that option from Drop Down menu.
Then go to Add-ons
Click on -> G.729 Annex A Codec -> Buy on Google Play or on iTunes.
You are done!
Here is what Groundwire looks like, when the SIP account is regsitered.