See also:

Using Softkeys to Control a USB Storage Device or iPod
The five softkeys below the radio display are used to control the functions listed below. To use the softkeys: 1. Press the first or fifth softkey below the radio display to display the functions li ...

Customer Assistance for Text Telephone (TTY) Users (U.S. and Canada)
To assist customers who are deaf, hard of hearing, or speech impaired and who use Text Telephones (TTYs), GMC has TTY equipment available at its Customer Assistance Center. Any TTY user can communicat ...

TTY Users
OnStar has the ability to communicate to the deaf, hard&-ofhearing, or speech&-impaired customers while in the vehicle. The available dealer&-installed TTY system can provide in-vehicl ...