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接入网介绍刘利亚接入网是在本地网中将各种不同的电信业务采用不同的传输媒质和传输技术集结到一个接入网中，再以接入网为单位传到交换机群。目前接入网的主要问题是本地网中原有的地下及空中电缆的利用问题。要实现在铜线对线上开放数字信号，只要利用２Ｂ１Ｑ的４位码...
Access network introduction Liu Liya access network in the local network will be a variety of different telecom services using different transmission media and transmission technology gathered in an access network, and then to the access network as a unit spread to the switch group. At present, the main problem of the access network is the use of underground and air cables in the local network. To achieve the online open digital signal on the copper, as long as the use of 2B1Q 4-bit code ...