Getting Straight Talk to work on the iPhone 4S with iOS 6+

I dropped my mega-cellphone service provider and decided to switch over to Straight Talk (ST) because I had heard good things about their service and that the monthly bill was $48 for everything unlimited - talk, text, and data! So, I bought the SIM card needed and the first month's service from the ST site. The SIM was plugged in, and the switchover was made on the ST site (they even ported my number for me). I now in theory had a better service (more minutes, data, etc) and was paying less for it.

Talk worked fine. SMS messages and Apple's iMessages worked fine. MMS messages, however, and internet data connectivity did not work. After a lot of reading, I discovered that the settings within the iPhone (called APN settings) were not configured correctly and that was why the MMS messages and data did not work properly. Information on how to fix this can be found on many sites, but no site got it quite right. Something was always missing. After much trial and error I pieced together a solution and have listed the steps below.

Before you start, go buy a used mini T-Mobile SIM card. This will be used to expose your iPhone's 'Cellular Data Settings' option later.

1. Remove any APN profiles that you've loaded (from unlock.co.nz for example).
2. Go to Settings / General / Reset / Reset Network Settings to clear out any settings that might be lingering.
3. Close all apps.
4. Open Notes app.
5. Open Settings app.
6. Turn off wifi.
7. Go to General / Cellular
8. Take out Straight Talk SIM. The iPhone will tell you there is no SIM.
9. Replace with T-Mobile SIM. Now tap 'Ok to dismiss'.
10. Turn the iPhone off.
11. Wait a few seconds and turn the phone back on.
12. Slide to Unlock. Wait until you see 'T-Mobile' as the carrier in the upper left corner of the screen.
13. Go to Settings / Cellular. You should now see the 'Cellular Data Settings' menu option.
14. Go into Cellular Data Settings.
15. Multitask over to Notepad.
16. Once in Notepad, take out T-Mobile SIM and put in Straight Talk SIM.
17. Wait for 'HOME' to appear in upper left of screen (may take 2 minutes or so)
18. Multitask to Settings (you should now be able to edit the fields). You should see 'PHONE' in a few of the fields.
19. Change the settings as follows:
    
    Cellular Data
    
    APN: att.mvno
    Username: (leave this field blank)
    Password: (leave this field blank)
    
    MMS
    
    APN: att.mvno
    Username: (leave this field blank)
    Password: (leave this field blank)
    MMSC: http://mmsc.cingular.com:80
    MMS Proxy: 66.209.11.33
    MMS Max Message Size: 1048576
    MMS UA Prof URL*: http://www.apple.com/mms/uaprof.rdf
    
    *If you have problems, try leaving this field blank
    
    NOTE: Some iPhone 4S users have trouble with the settings above. Putting the port on the proxy instead of the MMSC will often fix the problem. Try the settings above first, and if they don’t work then try using http://mmsc.cingular.com for the MMSC and 66.209.11.33:80 for the MMS Proxy.
    
    
20. Go to Settings and turn Airplane mode ON, wait until you see the plane in the upper left, then turn OFF
21. Turn off iPhone. Reboot.
22. Optional: Go to Settings / General / Cellular and turn cellular data OFF, wait a few seconds, then turn back ON
23. At some point down the road the iPhone starts acting like it forgot the settings you put in, just repeat steps #20 and #22. That should fix it.

If you update your iPhone's operating to another version, you'll have to go back and redo all of the steps above.

That's it. Hope this has helped you!