Upon detection of {HEAD ~ a trigger}, such as {TAIL ~ the exceeding} of an error threshold or the direction of a user, a diagnostic link system enters a diagnostic information transmission mode 
such as
Upon detection of { HEAD ~ a trigger } , such as { TAIL ~ the exceeding } of an error threshold or the direction of a user , a diagnostic link system enters a diagnostic information transmission mode
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH