See also:

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 ...

Overview
The GMC Sierra All Terrain HD concept is an exploration of heavy-duty truck capability combined with greater off-road versatility. It is highlighted by a bold exterior design, enhanced all-terrain ...

Using the “Dial” or “Call” Command
1. Press and hold for two seconds. 2. Say “Dial” or “Call.” 3. Say the entire number without pausing, or say the name tag. Once connected, the person called will be heard through the audio ...