Call waiting

Could some possible give me a heads up on call waiting?

I have seen there is an option in the feature codes but I am not sure how this applies.

I am looking for a potential solution whereby if a call is active and someone else rings the caller can be essentially put on hold.

Thanks for any help.

Regards

Hi
i am also looking for the same so any body help us.
how we can configure dial plan if we are using sip technilogy to make call waiting in asterisk.
plz help us.

Thanks