I read the manual on page 174 and it's not a lot of help really.
It sounds like you get the option turn it on and off once you're connected to a tty machine. The option would appear in the Phone app
here you go:
(although there's no such seting on my Phone)
Message was edited by: Dave Hutch
Note, if your phone is officially unlocked & you are using a sim from a carrier NOT on this list, TTY will be enabled by default:
If that's not the case for you, then Settings>Reset>Rest All Settings...should get rid of the TTY icon.
Sunrise, my Swiss Provider is not on that list. But probably the list ist not up to date, because Sunrise is an iPhone Provider since two weeks in Switzerland! The other two Provider (Orange and Swisscom) are on the list.
I can remember, that I had the tty button in settings on one of my earlier iOS Version and I turned it on (don't ask why) ...
If I reset the settings, do I loose a lot of other settings as well?
I also have this TTY icom problem and cannot seem to disable it.
My sister bought iphone4 for me from HK. She used her sim to activate this phone and try to see if there's any problem. Her sim is Smartone-Vodafone which I believe is on the list (http://support.apple.com/kb/HT1937).
Then, I'm in Thailand and using AIS which is on the list also.
Referring to http://support.apple.com/kb/HT3519, they said
Note: Inserting a SIM into an unlocked iPhone from a carrier not found on this list enables TTY.
So, I guess the 1st sim (Smartone-Vodafone) was originally NOT on the list. And there's no option under Settings > Phone to disable it.
Besides the reset option which will erase all my preferences, any other option to clear this TTY icon ?
If I back up my iphone via itune and reset, then restore, will it clear TTY icon ?
Thanks in advance for any reply and suggestions
I guess you didn't read the subject nor the question: lot of people here - and I - don't have the Settings/Phone/TTY switch.
I suspect the issue is not related to the SIM, but to the language.
It seems this TTY switch only appears when the language of the iPhone is English.
So the only solution is to reset the settings of the iPhone... Or to re-install the system... like people used to do with PC Windows in the 90's.