(3) The answer-back capability available on many terminals 

 will respond to the WRU. At terminals not thus equipped, 

 the operator will respond with the user ID (a maximum of 



six characters). Optionally, he/she may enter his/her user ID, 

 a comma, and one of the following: MSG , DIS, RLT, or the 

 time (in the form DDDHHMMSS of GMT). 



(4) The CDF determines whether the ID is valid, and, if only 

 the ID was entered, determines whether any new message 

 data have been acquired since the previous user inquiry. 



(5) If the ID is invalid, the request is repeated up to five 

 times, after which the CDF goes on-hook after sending 

 the following message: 



TOO MANY ERRORS. 



(6) If the ID is correct, and if only the ID was entered, 

 CDF informs the user of the number of messages received 

 since the previous inquiry and the time of the last 

 dissemination. The CDF then transmits: 



ENTER MSG, DIS, RLT, OR STOP. 



(6a) MSG Directive - the user may transmit a text message to 

 the DCS operator (to be printed on the console) by 

 entering MSG after the CDF informs him/her of the number of 

 messages received since the previous inquiry (or by 

 entering MSG with the ID entry, separated by a comma). 

 The CDF responds with ENTER MESSAGE, after which the 

 user may enter the message. 



(6b) DIS Directive - the user may request transmission of the 

 sensor platform data by entering DIS after the CDF 

 informs him/her of the number of messages received since the 

 previous inquiry (or by entering DIS after the ID entry, 

 separated by a comma). 



Transmission of sensor platform data, if requested, begins 

 with the oldest undisseminated message and continues to 

 the newest message on the user's queue. Abnormal platform 

 response messages are transmitted in lieu of data when 

 appropriate, and are identified by two carets (AA) 

 preceding the test of the message. 



Alternatively, the user may specify a new time (other 

 than "time of last inquiry") from which dissemination 

 of data in the queue may begin, by entering DDDHHMMSS 

 (in GMT). 



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