Cardo Packtalk Bold

Hi Folks.

Finally got round to changing our intercoms and have some questions relating to the new ones.

I bought a duo set and it seems we can speak rider to pillion by either bluetooth or DMC, but which to use? Is one more reliable than the other?

We want to be able to listen to our own music or share, how do we toggle between?

Any other tips gratefully received.

Thanks

Howard