Bluetooth with DUN and HFP

Hi all,

I have to simulate a mobile phone connection to the car ECU. I have a linux with SUSE11 running to simulate the mobile phone. It has blueZ utils.

I would like to know if I should have separate serial connections (rfcomm0 and rfcomm1) to run DUN and hands free(HFP)protocol to the car ECU or can these protocols work on the same rfcomm channel?

Thanks in advance