随着直拨用户的迅速发展,长途全自动业务量每年以40—50％的速度上升,市县传输电路极其紧张。在明线复用已不可可能满足要求的情况下,怎样解决在近距离大容量的数字传输信道建立起来前的市县传输问题。笔者提出了一种既实用、经济又能满足技术要求的市县传输过渡方案 With the rapid development of direct dialing users, long-distance automatic business volume every year 40-50% of the rate of rise, county transmission circuit extremely nervous. How to solve the problem of transmission in cities and counties before the establishment of digital transmission channels with high capacity and short distance under the circumstance that it is impossible to meet the requirements through the reuse of bright line. I proposed a practical and economic and can meet the technical requirements of the county transfer transition program