Test methods for headphones used primarily for speech 主要适于演讲用头戴耳机的测试方法
2.
Minimum performance requirements on high fidelity headphones 高保真头戴耳机最低性能要求
3.
General specification for headphones 头戴耳机通用技术条件
4.
Methods of measurement on headphones 头戴耳机测量方法
5.
Established in february 2001 ， gn netcom ( china ) ltd . was put into operation on may 1st as a major supplier of manufacturing and processing hands - free headset and wireless headset with 90 % of its products abroad oriented 成立于2001年2月的大北欧通讯设备（中国）有限公司在2001年5月正式投产，主要生产加工各种头戴耳机及蓝牙耳机，产品80 ~ 90外销。
