In some embodiments audible and visual indication can be provided on the assemblies indicating {TAIL ~ successful exchange} of {HEAD ~ the pairing information} 
In some embodiments audible and visual indication can be provided on the assemblies indicating { TAIL ~ successful exchange } of { HEAD ~ the pairing information }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD