ETSI PRETS 300 488-1995 终端设备(TE).听力受损者使用的电话.为听力受损者提供额外接收放大功能的电话装置特性
Terminal Equipment (TE); Telephony for Hearing Impaired People; Characteristics of Telephone Sets That Provide Additional Receiving Amplification for the Benefit of the Hearing Impaired