2010 Buick LaCrosse Owner's Manual - Page 209

Infotainment System Mute or UnMute a Call 1. Press the 6-65 5 hard key. 2. Select the Mute call option to mute the call. 3. Select the Mute call option again to unmute the call. Dual Tone Multi-Frequency (DTMF) Tones The in-vehicle Bluetooth system can send numbers during a call for "Dial 1 or 2", for phone number extensions, or voice mailboxes. 1. Press the 5 hard key. 2. Select "Enter Number" option and enter the number sequence.