AN SF340 CREW IS CONFUSED BY BEING UNABLE TO DIFFERENTIATE BTWN THEIR CALL SIGN AND ANOTHER COMPANY CALL SIGN WHILE ON THE WRONG FREQ WITH APCH CTLR AT MEM; TN.

Narrative

APCHING MEM INTXN FROM THE SE; WE WERE HANDED OFF TO MEM APCH (119.1) BY ZMA. NORMALLY THIS IS A W SIDE OF THE AREA FREQ; BUT THE DAY BEFORE WE WERE GIVEN AN E SIDE FREQ APCHING MEM FROM THE W; SO THIS DID NOT SEEM COMPLETELY OUT OF PLACE. WE CHKED IN WITH APCH AND WERE GIVEN A DSCNT TO 6000 FT AND A TURN TO 350 DEGS. THE FO WAS WORKING THE RADIOS AND I TOLD HIM TO VERIFY THE CLRNC BECAUSE IT SOUNDED LIKE WE WERE REFERRED TO AS A-- INSTEAD OF B--. THE CTLR VERIFIED THAT THE CLRNC WAS FOR US (B--) WE COMPLIED AND SHORTLY THEREAFTER HEARD THE CTLR TELL ANOTHER ONE OF OUR FLTS THAT HE NEEDED HIM TO START HIS DSCNT TO 6000 FT NOW. THE COMPANY ACFT RESPONDED THAT THEY HAD NOT BEEN ISSUED A CLRNC TO 6000 FT (HIS CALL SIGN WAS BXY AND OURS WAS BYZ; BUT THE CTLR'S PRONUNCIATION WAS SUCH THAT YOU COULD NOT DISTINGUISH BTWN THE TWO). I MENTIONED TO THE FO AT THIS POINT THAT THERE WAS MISCOM GOING ON BECAUSE OF THE WAY THE CTLR WAS PRONOUNCING OUR SIMILAR CALL SIGNS. THE FO THEN TOLD THE CTLR THAT WE COULD NOT TELL THE DIFFERENCE BTWN HIS PRONUNCIATION OF BXY AND BYZ. THE CTLR THEN INFORMED US THAT WE WERE ON THE WRONG FREQ. WE SWITCHED TO THE STANDARD E SIDE FREQ (125.8) AND THE REMAINDER OF THE FLT WAS UNEVENTFUL. I CALLED THE APCH FACILITY ABOUT 1 HR LATER AND SPOKE WITH THEM ABOUT WHAT HAD OCCURRED; AND WAS TOLD THAT THEY WERE DISCUSSING THAT VERY THING AT THAT MOMENT. I WAS TOLD THAT WE HAD BEEN GIVEN THE WRONG FREQ FROM THE CTR AND THAT THE CTLR WAS GIVING US CLRNCS BECAUSE HE WAS EXPECTING TO HEAR FROM BXY (NOT BYZ). THE PERSON I SPOKE WITH SAID THAT THERE WERE NO CONFLICTS CREATED BY THIS SIT; AND THAT THE PARTIES INVOLVED WERE URGED TO LISTEN CAREFULLY TO THE CALL SIGNS.