[Spooks] Mystery CW

[mslaten]

Hi Group:

    Last night I ran across an unidentified CW transmission.  It was on
10724m at 0345z.  No callsigns were heard in 45 minutes of listening.  The
following was heard:

1.    Cut numbers used in both the message preambles and the messages.
2.    Cut numbers were AU34567DNT, representing 1234567890.
3.    Messages were 5-digit groups.
4.    Transmission was handsent.
5.    The sender was working with an outstation.  I was unable to locate it.
6.    Preambles were:
      NR UT7 W 117 BT (Then into traffic).  The UT7 means 207.
7.    Heard sender transmit message numbers 206 through 214 before dropping
for further search.
8.    W probably stands for number of groups in message.
9.    Each message consisted of a different number of groups.
10.  Other chatter heard:
         IMI    =    interogatory
         AS    =    please wait
         EEEEE =  made a mistake, and repeats
         AR    =    end of message
         OK    =    OK
         GA    =    go ahead

    Does anyone have an idea who this may be?  Could it be US military?
    Could it possibly be M77 (P7X)?

73's
Mark