Terminal equipment - telephony for hearing impaired people - characteristics of telephone sets that provide additional receiving amplification for the benefit of the hearing impaired ; english version ets 300488 : 1996 终端设备.听觉损伤者用电话.带声音接收放大装置的听
2.
Terminal equipment - telephony for hearing impaired people - characteristics of telephone sets that provide additional receiving amplification for the benefit of the hearing impaired 终端设备.听觉损伤者用电话.使听觉损伤者受益的提供附加声音接收放大装置的电话机组的特征