本文介绍的一种半自动型电话交换机(专利产品),以一条外线转换多部分机,可以同时提供一组内线、外线通话,互不干扰。作为一部人工值守型小型电话交换机,它结构简单,适于农村、乡镇、厂矿及中小学校、旅馆等单位团体使用,根据需要可选用 This article describes a semi-automatic telephone exchange (patented product), with an external conversion multi-part machine, you can also provide a group of internal and external calls, without disturbing each other. As a small, hand-held small telephone exchange, it has a simple structure and is suitable for use in rural areas, townships, factories, mines and schools, hotels and other units, as required