民主德国通信电子联合企业在光通信领域从事科研和试验设计已有多年历史。通信容量为120话路的光纤传输系统就是该企业与其它企事业单位共同研制的一个产品。该产品于70年代末开始在柏林试用。尔后在试用基础上制成DUS-LL—8型光导波传输系统。该系统从80年代初列 Democracy Germany’s telecom conglomerates have been engaged in scientific research and experimental design in the field of optical communications for many years. Optical fiber transmission system with 120 channels of communication capacity is a product jointly developed by the enterprise and other enterprises and institutions. The product began its trial in Berlin in the late 1970s. Then made on the basis of trial DUS-LL-8-type optical waveguide transmission system. The system is listed from the early 1980s