what's the code you type into a fax number to keep the line clear?

[Mandelon]

I recall there used to be a number code you typed into a fax machine to keep the line clear from other callers, if you had call waiting? I brought a fax home from work so I could send some papers out from here, and cant' remember.
Anyone know? Thanks.

[Cheap Thrills]

*70
C.T. :wink:

[jimslade]

*70,,

[Larry H Parker]

It only works if you are not faxing a toll free #.