CREW WAS GIVEN A DSCNT CLRNC ALONG WITH A FREQ CHANGE. ON CHKING IN SOME CONFUSION OVER VALIDITY OF CLRNC; ANOTHER FREQ CHANGE CONFIRMED CLRNC.

Narrative

INBOUND TO CHICAGO ON THE JANESVILLE ARR WE WERE GIVEN A FREQ CHANGE PRIOR TO JANESVILLE VOR. JUST AFTER CHKING IN WITH THE NEW FREQ WE WERE GIVEN A DSCNT FROM FL240 TO 14000 FT; MAINTAIN PRESENT HEADING AND WERE TOLD TO EXPEDITE DSCNT. I RESET THE ALT ON THE MODE CTL PANEL; AND IT WAS CONFIRMED BY THE PF. I READ BACK THE CLRNC AND RPTED OUT OF FL240 FOR 14000 FT. I ASKED THE CTLR FOR THE ALTIMETER. HE ASKED WHO CALLED AND I REPEATED OUR FLT NUMBER AND SAID WE NEEDED THE ALTIMETER AND AGAIN SAID WE WERE OUT OF FL240 FOR 14000 FT. THE CTLR THEN SAID YOU HAVE THIS FREQ IN ERROR AND GAVE US ANOTHER FREQ. WE WERE ALREADY 500-600 FT BELOW FL240 SO WE STOPPED DSCNT AND LEVELED BACK AT FL240. WHEN I CHKED IN WITH NEW FREQ I TOLD HIM WE HAD BEEN CLRED TO 14000 FT BUT SINCE THE OTHER CTLR THEN HAD SAID WE HAD THAT FREQ IN ERROR WE WANTED TO MAKE SURE THAT CLRNC WAS FOR US. HE SAID YES; AND GAVE US THE SAME CLRNC AS THE LAST FREQ. WE WERE CLRED TO 14000 FT; EXPEDITE DSCNT AND MAINTAIN PRESENT HEADING. THE REMAINDER OF THE FLT WE ENCOUNTERED NO MORE UNUSUAL COMS.