An alternative method of line selection is illustrated in FIG 20 in which {HEAD ~ the switch panel} contains only 4 switches 61, 63, 63, 64 and {TAIL ~ a line count display} 65 
contains
An alternative method of line selection is illustrated in FIG 20 in which { HEAD ~ the switch panel } contains only 4 switches 61 , 63 , 63 , 64 and { TAIL ~ a line count display } 65
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH