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引言FREQUENTIS VCS3020S内话系统是一套全数字的语音通信系统。其操作席位与中心交换系统是利用双绞线进行连接的,由于受到双绞线传输距离的限制,中心交换系统与操作席位间的传输距离不能超过200米。随着对远程监控技术需求的不断增加,延伸中心交换系统与操作席位间的距离十分
Introduction The FREQUENTIS VCS3020S internal phone system is an all-digital voice communication system. The operating seat and the central switching system are connected using twisted pair cables. Due to the limited transmission distance of twisted pair cables, the transmission distance between the central switching system and the operating seats can not exceed 200 meters. As the demand for remote monitoring technology continues to increase, the distance between the extended center exchange system and the operating seats is very high