{HEAD ~ sensors} for identifying {TAIL ~ types} of the installed optical parts which have been installed in the main equipment; and 
for identifying
{ HEAD ~ sensors } for identifying { TAIL ~ types } of the installed optical parts which have been installed in the main equipment ; and
HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH