{HEAD ~ The other modem} is typically located at {TAIL ~ the central office} and is “upstream” from the customer premises 
is typically located at
{ HEAD ~ The other modem } is typically located at { TAIL ~ the central office } and is “ upstream ” from the customer premises
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH