The characters and {HEAD ~ graphics} transmitted through {TAIL ~ a data channel} are displayed clearly to the viewer by an ingenious technique devised for displaying characters and graphics of a supplementary program 
transmitted through
The characters and { HEAD ~ graphics } transmitted through { TAIL ~ a data channel } are displayed clearly to the viewer by an ingenious technique devised for displaying characters and graphics of a supplementary program
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL 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