Multiple commlinks, acking related questions Options

[EuroShadow]

I have gathered that in shadows proffesionals use multiple commlinks, which makes sense: you may want to use one for public use, one extremely safe and stealthy for your own PAN; your devices; your bank accounts; one safe and stealthy for job related stuff.

And you may ditch one if its Acess ID gets known with a wrong guys.

But when you ditch and take new commlink or use other one to call your fixer: does he knows its you? And the related question: when you call someone and have a chat, does he get to know your Access ID?

In my mind, it is like me calling someone from laptop using Skype: even if i change my laptop, my skype account is the same and the other person knows it is me. But he cannot trace my IP, right?
So what's the deal with commlinks? And even if i know the location of his PAN - can i get his commlink's Acess ID?

thank you.