This message was sent by a homeland "Y Station", most likely from the RAF, to a decoding facility downstream, in the SIGINT community. At Bletchley or elsewhere. Y Stations were monitoring German military communications from the UK. It is why what we can now read on paper is the verbatim retranscription of a procedure that was heard on a radio receiver by a radio intelligence operator, --ie the presence of the standard "checksum" and EOM signature comprising the reiteration of the header group followed by the total number of 5-groups sent -- 27 in the instance. The origin time "1522" is the ZULU at which the actual transmission started while the end of transmission time is written after the checksum "1525/6". Taking pauses into account, this means the morse code operator was transmitting the groups at 10wpm, a credible speed for this type of operation. I hope this helps. Greetings from rainy Montreal David Thorne-Alexander http://en.wikipedia.org/wiki/Beaumanor_Hall