What does ATC mean by this?

[RyanB]

Was listening to some LiveATC and i heared something like this, cross 30 miles south of Atlanta at or maintain FL320?
One flight was going to Chattanooga and they said bluestreak 5100 cleared direct chattanooga, then they said bluestreak 5100 cross 60 miles south of chattanooga at or maintain FL180

 

[kgruber]

You heard it incorrectly. Substitute "and" for "or."

 

[coma24]

Those are crossing restrictions. It wouldn't have been "at OR maintain..." it would've been "at AND maintain."

ATC is telling the pilot that he/she must be at that flight level by that point in space. The pilot can then initiate the descent at their discretion.

Edit: evidently I'm a slow typist, and/or I say too much.

 

[RyanB]

Makes sense, yes i understood it wrong, thank you