在一张桌上放着两部或多部电话机,当铃声响起时难以区分是哪一部电话机在响铃。本文介绍的给电话机加装来铃指示灯电路,可使电话机来铃时具有声、光显示功能,给接电话者带来一定的方便。电路如图1所示。其中虚线左侧为电话机原振铃电路,右侧为加装的电路。由图可见,振铃IC的振荡信 Placing two or more telephones on a desk makes it hard to tell which one is ringing when the bell rings. This article describes the installation of the telephone ring to the light circuit, the phone can ring when the sound, light display, to the caller to bring some convenience. Circuit shown in Figure 1. The left side of the dotted line for the telephone ringing circuit, the right side for the installation of the circuit. Can be seen from the figure, ringing IC’s oscillation letter