detecting and saving {TAIL ~ a called extension number} sent by {HEAD ~ said central office} from a calling party on a direct in dial trunk line into said PBX, 
detecting and saving { TAIL ~ a called extension number } sent by { HEAD ~ said central office } from a calling party on a direct in dial trunk line into said PBX ,
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH