Android Sip is an option on Android devices. Android SIP allows you to make calls through an Internet call account (also called SIP account). These calls are made through SIP (Session Initiation Protocol) and any data connection available in WiFi.
The Internet call feature is available on Android even in the device that has a SIM card slot for making calls. You can add a SIP account to receive and make calls over the Internet on Android. Here is how
1.First, you must obtain a SIP account. You can get a free SIP account by registering with callcentric.com. Once the registration is complete, you will receive your SIP account number (username), your password and the name of your server (usually identical to the domain name). Write them before moving on to the next step.
2. On your Android phone, open the call interface by touching the phone icon on the home screen.
3. Press the menu button on the device or touch the menu icon (three vertical dots) in the lower right corner and select Settings from the menu.
4. On the configuration screen, scroll down and touch Account in the Internet call settings section.
5. On the Internet Calling Account screen, you can select Receive incoming calls if you want to receive phone calls over the Internet. Then touch Add account next to the screen at the top right.
6. Enter the details of your SIP account. As a general rule, you must enter the user name, password and SIP SIP server. There are also optional configurations, but you can leave them as they are.
7. Touch the Save button in the upper right corner of the screen to save your account settings.
8. Return to the Phone Call Settings page, touch Use Internet calls to choose when to use the Internet call account (SIP). You can choose to use the SIP account whenever a data or Wi-Fi account is available, only for Internet calls or a request each time you make a call.
SIP accounts allow you to have a virtual phone number that you can give everyone so they can call this number through any type of phone. There are dozens of free SIP account providers in the world and everyone can give you a free SIP phone number. For example, callcentric.com provides you with a SIP number from the United States. While Net Telco offers a range of telephone numbers from the United Kingdom.