MD80 CREW DSNDED BELOW THEIR CLRED ALT.

Narrative

ALTDEV. JUST DEPARTING AUSTIN; WE WERE AT ABOUT FL205 CLBING TO FL210 WHEN I RECEIVED AN RA WHICH I FOLLOWED; AND AT ABOUT THE SAME TIME I DISCONNECTED THE AUTOPLT AND AUTOTHROTTLES TO MANUALLY FLY THE ACFT. WE WERE ENTERING A LITTLE AREA OF RAIN SHOWERS WHICH I ALSO WAS DEVIATING. EVIDENTLY AT THIS SAME TIME; WHILE I WAS DOING ALL THIS; WE RECEIVED A CLRNC TO CROSS HIRST INTXN AT 11000 FT. WHEN THE ACFT WAS NOW AT FL210 AND STABILIZED FROM THE RA; I WAS TOLD FROM FO OUR CLRNC WAS TO CROSS HIRST AT 10000 FT. I DID SO AND WAS LEVEL AT HIRST AT 10000 FT WHEN WE WERE NOW TALKING TO DFW APCH; WHO TOLD US TO CLB AND MAINTAIN 11000 FT AND THAT THAT SHOULD HAVE BEEN OUR ALT. WE CLBED TO 11000 FT AND ASKED HIM IF THERE WAS A CONFLICT. HE SAID NO. MY COPLT IS SURE HE HEARD THE RESTR AS 10000 FT. I SHOULD HAVE HEARD THE CLRNC MYSELF BUT I DID NOT. I WAS QUITE BUSY FLYING THE ACFT AT THE TIME. SUPPLEMENTAL INFO FROM ACN 418569: WE WERE AT FL210. ZHU GAVE US A XING RESTR TO DSND AND CROSS HIRST INTXN AT WHAT I UNDERSTOOD TO BE 10000 FT. I DIALED IN 10000 FT ON THE ALT SELECTOR. I THOUGHT I READ BACK 10000 FT. AFTER A FEW MINS WE BEGAN OUR DSCNT TO MEET THE XING RESTR AND I RPTED OUT OF FL210 FOR 10000 FT. ZHU THEN SWITCHED US OVER TO DFW APCH AS WE WERE LEVELING OFF. WHEN I CHKED IN WITH DFW APCH I RPTED OUT OF 11300 FT FOR 10000 FT WITH THE ATIS. AFTER LEVELING AT 10000 FT; APCH SAID TO MAINTAIN 11000 FT. WE CLBED BACK TO 11000 FT.