{HEAD ~ Each transformer} 28, in {TAIL ~ association} with the link 18, thus serves to transmit signals between the surface installation 16 and the tool in question 
{ HEAD ~ Each transformer } 28 , in { TAIL ~ association } with the link 18 , thus serves to transmit signals between the surface installation 16 and the tool in question
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL 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