A bus coupler for exchanging {HEAD ~ data} between a network constructed for transmitting Ethernet telegrams and {TAIL ~ a lower level bus system} , comprising: 
between
A bus coupler for exchanging { HEAD ~ data } between a network constructed for transmitting Ethernet telegrams and { TAIL ~ a lower level bus system } , comprising :
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH