{HEAD ~ The timer}, comprising {TAIL ~ digital circuitry} is easily interfaced to a digital control computer 
comprising
{ HEAD ~ The timer } , comprising { TAIL ~ digital circuitry } is easily interfaced to a digital control computer
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH