سؤال 111What digital protocol is used by APRS?PACTORQAMAX.25✓پاسخ درستAMTORتوضیحAPRS packets are ordinary amateur packet radio frames, so the link layer is AX.25 and any TNC that speaks AX.25 can send and receive them. PACTOR and AMTOR are HF ARQ modes, and QAM is a modulation scheme rather than a protocol.