AN MD80 EXPERIENCED 2 TCAS RA'S ON FINAL TO DFW RWY 17C. THE FIRST RA WAS CLBING; THE SECOND DSNDING. ATC RPTED NO TFC. NO PAX ELECTRONIC DEVICES RPTED.

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WE WERE BEING VECTORED BY DFW APCH CTL FOR AN ILS APCH TO RWY 17C. WE WERE LEVEL AT 5000 FT IN IMC. A TARGET APPEARED OUT OF NOWHERE AT OUR ALT AND LOOKED TO BE SUPERIMPOSED UPON OUR ACFT. WE GOT AN IMMEDIATE TFC ALERT FOLLOWED BY A COMMAND TO CLB AT A RATE IN EXCESS OF 2500 FT. I DISCONNECTED THE AUTOPLT AND FOLLOWED THE TCAS RESOLUTION. THE TARGET CONTINUED TO SHOW LEVEL AT OUR ALT EVEN AS WE CLBED TO 6400 FT. WE ADVISED APCH CTL THAT WE WERE RESPONDING TO AN RA. WE WERE RECLRED TO DSND TO 4000 FT AND GIVEN VECTORS TO CONTINUE THE APCH. AFTER WE WERE ESTABLISHED ON THE GS WE GOT ANOTHER SIMILAR WARNING WITH AN ACFT SUPERIMPOSED ON OUR POS AND AGAIN AT THE SAME ALT. THIS TIME THE COMMAND WAS TO DSND; BUT BEFORE I COULD TAKE ANY ACTION; THE TARGET AND WARNING DISAPPEARED. THE FLT CONTINUED WITHOUT ANY FURTHER INCIDENTS. WE WROTE UP THE TCAS SYS FOR MAINT ACTION ON ARR AT DFW. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT HE HAS NOT RECEIVED ANY ADDITIONAL INFO ABOUT THIS EVENT. HE DID NOT CONSIDER THAT THE FALSE RA WAS PAX ELECTRONIC DEVICE INTERFERENCE BECAUSE OF THE ALT AND THE FLT ATTENDANTS NOT RPTING PAX ELECTRONIC DEVICES IN USE.