目前,大多用机械式电铃作为电话的呼叫信号,该电铃噪声大、音调单纯、听起来较刺耳,现利用一块音乐集成电路为电话装配一个音乐式电话铃,其声调非常优雅动听。如果在数部电话中安上不同曲调的音乐集成电路(IC),当把这些电话安装在同一场所时,就可根据曲调的不同区别出哪部电话在呼叫。电路如附图所示,在音乐IC的触 At present, most mechanical bells are used as call signals for telephone calls. The bells are noisy, simple in tone and more jarring. A music integrated circuit is now used to assemble a music-style telephone bell for the telephone, and the tone is very elegant and graceful. If you install music ICs with different tunes on several phones, you can distinguish which phone is calling based on the tunes when you install the phones in the same place. Circuit as shown in the figure, touch the music IC