I'm somewhat disappointed with my Bluetooth functionality with my 2007 STS. I have a privately owned cell through Verizonand a company owned cell through Sprint. Iwas able to getboth my cell phones linked up and I was able to make calls using the display dialer. That works perfectly. So I started to mess around with the voice activated commands and to my surprise it only works with the ONSTAR, which charges big bucks for this service and minutes. I got two cell phones already and several Bluetooth headsets. Why would I want to pay ONSTAR for the same thing? Not to mention my Bluetooth headsets have mute buttons which only mutes the microphone and I haven't found that ability yet on my audio system. Are there any other options available? Well maybe because I didn't get a manual or because it's really had to find thing in the PDF but I did find this regarding the 2008 STS-V and it seems to work with my 2007 STS too.

Voice commands also can be used to make phone calls via the STS-V's standard Bluetooth hands-free calling interface. Pairing our phone to the system was very straightforward using the CONFIG hard button on the head unit. Car and phone found each other immediately, and we were then able to make calls either manually via the touch screen keypad (which is curiously called up by pressing the AUX button); or by voice dialing (say "telephone enter" to prepare the system to receive spoken numbers).