YD/T 638.5-1993
电话交换机型号命名方法
Type designation system for telephone switchboards
1993-08-17
SJ 3179-1988
矿用纵横制用户电话交换机测试方法
Methods of measurement for iron clad crossbar subscriber's telephone switchboards
1988-04-07
ITU-T Q.29
Causes of noise and ways of reducing noise in telephone exchanges
电话交换机噪声产生的原因及降噪方法
1988-11-25