This is not related to voice at all, this is all ESXi/VMWare.
You can use either port, it will depend on the routing you have configured for each (and vlans for port 1), and the vSwitch config you're using for that VM, but again, this is not related to voice.
You might want to ask this in the VMWare communities, or if your company has a DC guy, ask him for assistance with this.
HTH
java
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