The feature of the ISD (Individual Speech Device) is that it adopts direct analogue record and access technique, and that speech signals, in their original forms, are recorded into analogue memory devices directly and can be preserved for a long period.

• 指出ISD单片语言器件的独特之处，是采用直接模拟存储技术，语音信号以其原本的模拟形式直接存入模拟量存储器中并长远保存。