POTENTIAL CONFLICT GND AFTER UNAUTH RWY ENTRY BY C-152.

Narrative

AFTER COMPLETION OF RUNUP CHKLIST; MYSELF AND 1 OTHER C- 152 CONVERGED UPON HOLD LINE AT RWY 17L. I ARRIVED AT HOLD LINE BEFORE OTHER C-152. THAT PLT ADVISED 'READY TO GO; RWY 17L; SE DEP.' I CALLED IN RIGHT AFTER EXPLAINING I WAS #1 AT HOLD LINE; SE DEP AS WELL.' RESPONSE WAS; 'ROGER; POS AND HOLD' WITHOUT ACTUALLY SAYING MY CALL SIGN (TAIL NUMBER). I VERIFIED; 'POS AND HOLD' WITHOUT ACTUALLY SAYING MY NUMBERS AS WELL. I PULLED OUT ONTO THE CTRLINE TO SEE AN AIRBORNE KING AIR (FAA ILS CHK PLANE) APCHING ME FROM OPPOSING END OF RWY AT A HIGH CLOSURE RATE. TWR CTLR BECAME ANXIOUS AND STATED FOR UNAUTH ACFT TO REMOVE THEMSELVES FROM ACTIVE IMMEDIATELY. I WAS ALREADY MOVING OFF OF ACTIVE (EXPEDITIOUSLY). CTLR SAID 'HOLD SHORT' INSTEAD OF 'POS AND HOLD.' I HEARD 'POS AND HOLD' AND EVEN READ BACK INSTRUCTION. I LATER EXPLAINED TO TWR MGR (AFTER BEING INSTRUCTED TO CONTACT TWR) THAT THIS WAS A MISCOM AND A FIRST FOR ME. TOGETHER; WE CAME TO A SOLUTION THAT ANY TIME THERE IS THE SLIGHTEST CHANCE FOR MISCOM TO ALWAYS VERIFY TO WHOM IT WAS DIRECTED AND MENTION CALL SIGNS WITH EVERY READBACK INSTEAD OF RELYING UPON VOICE IDENT.