I'm not sure here, but I do know, when I am not connected to my wifi, I don't get any calls, once in a while I will get a message saying that I have a new VM..but when it is on, I get my calls...I guess only Samsung can answer this..I will post in their forums and come back here with a response.
Ok, so I chated with a Samsung Person. This phone DOES NOT HAVE WIFI CALLING. Here is the transcript:
Please wait for a Samsung Agent to respond.
All Samsung Agents are currently assisting others. Thanks for your patience. A Samsung Agent will be with you shortly.
You are now chatting with 'Pascal'. There will be a brief survey at the end of our chat to share feedback on my performance today.
Your Issue ID for this chat is
Pascal: Hi, thank you for contacting Samsung Technical Support. How may I help you today?
Al: Hi, can you confirm, on a SGH-T989 cell phone. Can you make a wifi call if you hook up to your wireless router/modem in your house?
Pascal: I understand that you want information on Wi-Fi calling option availability for Samsung Galaxy S II SHT-T989, am I correct?
Al: Yes, that is correct..
Pascal: Thank you for the confirmation.
Pascal: I will assist you with it.
Al: Ok
Pascal: Would you mind holding 2 minutes while I gather the required information on your request?
Al: not at all...go ahead
Pascal: Thank you.
Pascal: Thank you for holding.
Al: ok
Pascal: I am sorry, Wi-Fi calling option is not available on Samsung galaxy S II SGH T-989.
Al: Ok, what is it when I hook it up to my wireless modem and make a call?
Al: when i do this, my signal bars become more, for better service, from what I was told
Pascal: Please allow me to go through the inquiry.
Al: Ok..
Pascal: Thank you.
Pascal: Thank you for holding.
Al: np
Pascal: I understand that you are getting better signals, service and voice quality, however Wi-Fi calling is not available on this device.
Al: Ok
Pascal: Can I help you with anything else?
Al: Will it become available in the future?
Pascal: I am sorry we do not have any information on future upgrade of the device.