CPR X HAD LTSS FROM ACR Y. SYS ERROR.

Narrative

THE INCIDENT BEGAN WITH MY D-SIDE INITIATING A HDOF TO THE MCW SECTOR ON CPR Y; SWBOUND FROM THE COTON SECTOR INTO THE MCW SECTOR. AROUND THIS TIME I WAS VECTORING AN ACR OFF COURSE FOR INTRAIL TO ORD WHEN ACR Y FIRST CHKED ON MY FREQ. I HEARD THE ACFT STATE THAT HE WAS LEVEL AT FL330; EXPECTING FL290 70 MI E (OF MCW). HOWEVER; I WAS NOT POSITIVE OF THE CALL SIGN; BUT BECAUSE OF MY PRIORITY OF DUTIES; I DID NOT IMMEDIATELY VERIFY THE CALL SIGN. INSTEAD; I TURNED AN ACR TO JVL SO AS TO KEEP MY STRING OF ORD INBOUNDS EVENLY SPACED. AFTER DOING SO; I ASKED THE ACFT CALLING CENTER TO SAY AGAIN. ACR Y CHKED BACK ON; IT CONFIRMED THAT IT WAS THE ACFT I THOUGHT HAD PREVIOUSLY CALLED ON. HOWEVER; I UNDERSTOOD FROM HIS FIRST XMISSION THAT HE WAS LEVEL AT FL330; EXPECTING FL290. I DID NOT KNOW THAT HE HAD BEEN GIVEN A DSCNT CLRNC BY MCW. BY THIS TIME; MSP HAD TAKEN THE HDOF ON CPR X. MY D-SIDE INFORMED ME THAT MCW HAD TAKEN A POINTOUT ON CPR X AND I WAS TO KEEP THE ACFT. SOMEONE FROM THE E AREA CALLED ON MY LANDLINE. DURING THAT COORD; ACR Y RPTED OUT OF FL330. I DID NOT HEAR THIS XMISSION. MY D-SIDE; WHO WAS LISTENING TO THE FREQ; HEARD IT AND BROUGHT IT TO MY ATTN. I IMMEDIATELY TOLD ACR Y TO MAINTAIN FL330 AND TO TURN 30 DEGS L. ACR Y DID NOT RESPOND. I THEN GAVE ACR Y THE CLRNC TO MAINTAIN FL320 AND TO FLY A 030 DEG HDG AS WELL AS CALLING OUT THE TFC. ACR Y THEN RPTED OUT OF 30400 FT. I CALLED THE TFC AGAIN TO ACR Y AND THEN TO CPR X. CPR X RPTED THE TFC IN SIGHT.