[Asterisk-Users] Extensions to solve three way calling problem

[PHP Mechanic]

 > Threeway calling is similar. You can make a small impromptu conference
> that way with 2 internal phones and an external or 3 internal phones or
> even 1 internal and 2 external calls on separate phone lines. All of
> these are mixed inside of asterisk and the PSTN is non the wiser.

Thanks for clearing this up for me. The thing that still get's me is that 
the pstn is a little bit wise. It can perform the following:

1. Establish a call with the first person. You can call them or they can 
call you.
2. Press Flash/Recall on phone to put the first person on hold.
3. Wait until you hear the dial tone.
4. Dial the number of the second person.
5. Wait until you hear the second line ringing.
6. Press Flash/Recall and talk to the first person (they will hear the 
ringing tone too).

Can I make asterisk play ball with my telco?