REGIONAL JET ASSIGNED 16000 FT BY ZNY CTLR IS SWITCHED TO ANOTHER FREQ AND RPTS DSNDING TO 10000 FT. ALT DISCREPANCY IS NOT CAUGHT BY ARTCC CTLR RESULTING IN A LOSS OF SEPARATION WITH JETSTREAM AT 14000 FT.

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ACR X RECEIVED A DSCNT TO 16000 FT. ACKNOWLEDGED AND READ BACK FROM R26. R26 XFERRED COMS TO R11. ACR X DSND TO 10000 FT. AT 14000 FT; ACR X WAS 4 1/4 NM BEHIND ACR Y AT 14000 FT. REQUIRED SEPARATION AT 14000 FT IS 5 NM. ACR X RPTED ON SECTOR 11 FREQ COMMUNICATING TO ATC DSNDING TO 10000 FT. R11 STAFFING WAS ONE FPL MONITORING A DEVELOPMENTAL WHO WAS SUPPOSED TO RECEIVE OJT ON RADAR ASSOCIATE POS BUT WAS BEING APPROVED TO WORK THE RADAR POS; IE; BOOT LEG TRAINING APPROVED BY SUPVR. NEITHER THE INSTRUCTOR NOR THE DEVELOPMENTAL HEARD ACR X ADVISE DSCNT TO 10000 FT RATHER THAN 16000 FT AS CLRED. ACR X HIGH RATE OF DSCNT WHEN OUT OF 16000 FT; ACTION TO STOP AT 15000 FT NOT SUCCESSFUL BECAUSE OF RATE OF DSCNT. R26 AND R11 OBSERVED CONFLICT ALERT. R26 ALSO OBSERVED MODE C ALT BELOW ASSIGNED ALT -- BOTH IN FULL DATA BLOCK. NO EVASIVE ACTION TAKEN. ACR X INSTRUCTED TO MAINTAIN 12000 FT WHEN CTLR WAS ADVISED THAT THE ACFT WAS THROUGH 14000 FT DSNDING. I ASSUME THE FLC 'DIALED IN' THE WRONG NUMBERS. THEIR CLRNC WAS 10 MI S LRP AT 16000 FT.