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