FO SWITCHED RADIOS RATHER THAN FREQS.

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I SOMEHOW SWITCHED RADIO COM PANEL #2 FROM #2 VHF TO #1 VHF THINKING I HAD ONLY CHANGED FREQS ON THE #2 TO ENRTE AIR TO AIR FREQ. THIS WAS DONE WHILE HOLDING IN POS ON RWY 34 AND WAITING FOR A LNDG ACFT TO CLR THE RWY. AFTER ACFT WAS WELL CLR OF RWY; AND REPEATED ATTEMPTS TO CONTACT TWR FOR TKOF CLRNC; IT WAS DISCOVERED THAT #2 VHF WAS NO LONGER ON TWR FREQ. AFTER CHANGING BACK TO TWR; WE WERE INFORMED THAT RPTED ATTEMPTS BY TWR TO CLR US FOR TKOF WERE MADE AND THAT; DUE TO NO COM; ACFT ON FINAL APCH HAD TO GAR. AFTER APOLOGIZING FOR THE MISHAP; WE WERE INSTRUCTED TO CLR RWY AND TAXI BACK AND HOLD SHORT AGAIN. TKOF AND REMAINDER OF FLT PROCEEDED NORMALLY WITH NO FURTHER PROBS. THE DESIGN OF MD-11 COM PANELS IS DIFFERENT FROM PAST FLOWN ACFT. THE 3 DIFFERENT HEADS ALLOW YOU TO TUNE ANY OF THE 3 VHF RADIOS WITH THE PUSH OF A BUTTON TO CHANGE RADIOS. THE XMIT/RECEIVE PANELS ARE RIGHT NEXT TO THE COM HEADS AND HAVE SIMILAR BUTTONS. THIS DESIGN CAN LEAD TO CONFUSION; ESPECIALLY DURING NIGHT OPS.