Another algorithm is a time based algorithm which employs {TAIL ~ a real time clock} to establish preset time intervals during which {HEAD ~ each} of the access codes are used 
Another algorithm is a time based algorithm which employs { TAIL ~ a real time clock } to establish preset time intervals during which { HEAD ~ each } of the access codes are used
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH