SEXX01 PHEB 100345 TO HONG KONG OBSERVATORY JMA, TOKYO ALASKA TSUNAMI WARNING CENTER CENTRE POLYNESIEN DE PREVENTION DES TSUNAMI NAT. MET. OPS. CENTRE, MELBOURNE PACIFIC TSUNAMI WARNING CENTER -- ANNOUNCEMENT OF MESSAGING CHANGE FROM PTWC-- THE PACIFIC TSUNAMI WARNING CENTER WILL SOON START SENDING EARTHQUAKE OBSERVATORY MESSAGES OVER THE AFTN CIRCUIT BY A NEW METHOD. ONE CONSEQUENCE OF THIS CHANGE IS THAT MESSAGES WILL HAVE A MODIFIED HEADER STRUCTURE. FIRST, MESSAGES WILL CONTAIN THE NEW HEADER 'SEXX01 PHEB', INDICATING THEY ORIGINATE FROM PTWC. SECOND,INSTEAD OF THE PTWC ADDRESS 'PHEBYMYT', MESSAGES WILL CONTAIN THE ORIGINATION ADDRESS 'KWBCYMYX'. FOR EXAMPLE, WHERE BEFORE A MESSAGE MIGHT CONTAIN THE HEADER LINE 051800 PHEBYMYT IN FUTURE THIS LINE WILL BE REPLACED BY TWO LINES 051800 KWBCYMYX SEXX01 PHEB 051800 APART FROM THESE DIFFERENCES MESSAGES WILL BE IDENTICAL IN STRUCTURE TO THOSE YOU CURRENTLY RECEIVE. FOR A SHORT PERIOD PTWC WILL SEND DUPLICATE MESSAGES USING BOTH FORMATS, BUT AS SOON AS IT IS CLEAR THAT THE NEW METHOD IS WORKING PTWC WILL STOP SENDING MESSAGES WITH THE OLDER FORMAT. PLEASE CONTACT PTWC BY EMAIL AT COMMS@PTWC.NOAA.GOV IF YOU HAVE QUESTIONS OR CONCERNS ABOUT THIS CHANGE. THANK YOU. STOP