Dial facility [Address Book]

This may sound a strange question, when I access my address book, r/click & select "dial" what happens then? presumably it would dial out, & I could then have a "normal" phone conversation via the PC mike & speakers?
If this is the case, would the cost of the call be charged to my phone account, or be covered by my monthly ISP subscription?
Sorry to be so vague about this [ two years, & still learning!]

Clicking on dial will make a normal phone call to the corresponding telephone number entered in the address book.

You may be able to converse via the mic and speakers provided they are configured properly.

Since the call is made using a modem to a phone which has nothing to do with the ISP, therefore the cost of call will be charged to your phone account.

Also, if you are already online, your online-connection either will be disconnected and the call put through or you get the busy-tone.

Thanks both, in other words, I was right, but this would be perfect with broadband, which cannot be accessed from my area.