針對(duì)煤礦井下調(diào)度及緊急救援系統(tǒng)的需求，以DTMF編解碼模塊為核心，設(shè)計(jì)了具有自動(dòng)撥號(hào)功能的新型電話(huà)系統(tǒng)。該系統(tǒng)利用MT8880對(duì)DTMF信號(hào)的編解碼功能實(shí)現(xiàn)一鍵撥號(hào)和遠(yuǎn)程設(shè)置，通過(guò)檢測(cè)振鈴和忙音信號(hào)，完成自動(dòng)摘機(jī)和掛機(jī)過(guò)程，配合AGC等外圍電路達(dá)到話(huà)音清晰流暢的效果。

　　Abstract:

　　To meet the demand for mine scheduling and emergency rescue system， with using DTMF signal codec as the core， a new telephone system was designed with automatic dialing function. In the system， the DTMF signal encoding and decoding function of MT8880 was used to achieve one-touch dialing and remote setting. The circuit detects the ringing and busy signal， and then completes automatic off-hook and hangup. With AGC(Automatic Gain Control) and other peripheral circuits， the voice was regulated to a clear and smooth effect.