SIMILAR CALL SIGNS. ACR X FLEW WRONG HDG. PLTDEV.

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ACR X GIVEN A CLRNC TO CROSS JAKSEN INTXN AT 12000 FT AND 250 KIAS IMMEDIATELY FOLLOWED BY ANOTHER CLRNC TO CONTINUE TO SLOW TO 210 KIAS AND THEN AFTER JAKSEN DSND TO 7000 FT. JUST PRIOR TO JAKSEN WE RECEIVED THE CLRNC TO TURN R TO 150 DEGS. SINCE THIS WAS A TURN OPPOSITE THE ARR PROC; WHICH SHOULD HAVE BEEN A L TURN; THE COPLT QUESTIONED THE CTLR. THE IMMEDIATE RESPONSE WAS IN THE AFFIRMATIVE BUT THIS TIME WITHOUT A FLT CALL SIGN. SOON AFTER WE STARTED THE R TURN THE CTLR ASKED US WHERE WE WERE GOING AND TURNED US BACK L TO THE NORMAL ARR HDG. THERE WAS NO CONFLICT BUT THE POTENTIAL WAS FRIGHTENING. THE CTLR SAID HE WAS WORKING 2 FREQS AND THE CLRNC WAS FOR ONE OF OUR COMPANY FLTS; ON THE OTHER FREQ WITH A SIMILAR CALL SIGN. WE SHOULD NOT HAVE ACCEPTED THE CLRNC UNTIL WE HEARD IT REPEATED THE SECOND TIME; IN FULL; INCLUDING OUR FLT NUMBER. I ALSO BELIEVE THIS DANGEROUS SIT COULD HAVE BEEN PREVENTED IF WE COULD HAVE HEARD BOTH SIDES OF THE COMS BTWN THE CTLR AND OTHER ACFT ON APCH. I FIND IT REALLY HELPS ME KEEP TRACK OF WHAT IS GOING ON AND WHERE EVERYONE IS WHEN I CAN HEAR BOTH SIDES. THIS HAS BEEN A STRONG REMINDER FOR ME HOW EASY IT IS FOR BOTH PLTS AND CTLRS TO CREATE DANGEROUS SITS BY NOT USING PRECISE TIME PROVEN RADIO PROCS. I HAVE PLEDGED TO MYSELF TO BE MORE CAREFUL AND DISCIPLINED WITH MY RADIO PROCS AND TO ALWAYS CLARIFY -- NEVER ASSUME. SUPPLEMENTAL INFO FROM ACN 296039: WE WERE GIVEN SEVERAL SPD; ALT AND HDG CHANGES IN QUICK SUCCESSION. ON THE SECOND OR THIRD CALL WE WERE GIVEN A HDG CHANGE OF R TURN TO 150 DEGS. AS OUR CURRENT HDG WAS 210 DEGS; I RESPONDED 'ROGER; R TO 150 DEGS; THE LONG WAY AROUND(?)' APCH REPLIED IN THE AFFIRMATIVE. AS WE BEGAN THE TURN; APCH CALLED BACK WITH 'WHERE ARE YOU GOING?' APCH STATED THAT THE TURN HAD BEEN FOR FLT XY (WE WERE FLT X). THIS WAS AN OBVIOUS READBACK/HEARBACK PROB EXACERBATED BY HIGH WORKLOAD FOR BOTH THE CTLR AND CREW.