Via TMZ:

It all went down earlier this afternoon — when cops responded to a 911 call about a man who was threatening to jump off a building in downtown Atlanta … the same building where the Ryan Cameron Radio Show is based.

We’re told T.I. heard about the jumper on the radio — and called Ryan Cameron to see if there was anything he could do to help out with the situation.

Ryan Cameron tells us … he told T.I. to roll over to the building, where the rapper met with police and recorded a heartfelt video message which cops then played for the man on the roof.

We’re told after the man saw T.I.’s video. he agreed to step off the ledge … and met T.I. in the lobby, where the two were able to talk things out.