The iphone 4 communication is by bluetooth for both phone and audio/music features.
You pair the phone via bluetooth and then you are able to control the phone.
You don't need the usb connection, this connection is primarily to charge the device.
The level of control of your device is a function of whether you have the nav screen or not.
With nav you can download your contact list and select individual contacts to call on the screen.
Without nav you input your contacts by voice one at a time and then use voice dial to select who you want to call.
You pair the phone via bluetooth and then you are able to control the phone.
You don't need the usb connection, this connection is primarily to charge the device.
The level of control of your device is a function of whether you have the nav screen or not.
With nav you can download your contact list and select individual contacts to call on the screen.
Without nav you input your contacts by voice one at a time and then use voice dial to select who you want to call.